Such a question is really difficult, like an academic paper! In recent years, when the US trade deficit with China showed a rapid growth momentum, American political interest groups directly targeted at the RMB exchange rate and repeatedly asked China to adjust the RMB exchange rate. In April 2005, the US Senate initiated the legislative process by 67 votes to 33 votes, claiming that if China did not adjust the RMB exchange rate within six months, it would impose a punitive import tax of 27.5% on China products. On July 2, 2005, the central bank implemented a managed floating exchange rate system based on market supply and demand with reference to a basket of currencies, and the RMB was no longer pegged to the US dollar. One of the goals of exchange rate reform is to let the RMB appreciate to solve the trade imbalance between China and the United States. However, according to the statistics of China Customs, since the exchange rate reform, the RMB exchange rate has continued to rise, and the trade surplus between China and the United States is still growing. It seems that we can draw a conclusion from this phenomenon that RMB appreciation has no effect on narrowing the trade surplus between China and the United States. Unfortunately, this inference is not accepted by the American authorities, but we are faced with the embarrassing situation of RMB appreciation abroad and depreciation at home. The price level continues to rise and the economic bubble continues to expand, which is very similar to the situation in Japan in the middle and late 1980s. In the long run, the two-way trend of RMB will certainly enlarge the fragility of China's economic system. Therefore, it is necessary to use empirical research methods to test the relationship between exchange rate and Sino-US trade surplus, and clarify the real reason and essence of the US demand for RMB appreciation.

Cointegration analysis and Granger causality test

(a) Method selection and data description

In the traditional multiple regression analysis, the so-called "pseudo-regression" problem will appear because of the trend term in the non-stationary series. In contrast, cointegration analysis can effectively avoid the problem of "pseudo-regression", and Granger causality test based on cointegration analysis is more comprehensive and accurate in judging the causal relationship between variables. In view of this, this paper uses cointegration analysis and Granger causality test to study this topic. The specific analysis steps are as follows: unit root test; Co-integration test; Granger test. COFB in the article represents the monthly value of China's trade surplus with the United States; EXRA stands for the exchange rate of RMB against the US dollar. Considering the timeliness of the impact of exchange rate on trade, this paper selects the exchange rate on the first working day of each month as the exchange rate of the current month.

(2) Metrological analysis and results

1. Unit root test of sample data. Unit root test, also known as the test of the stationarity of time series data, mainly tests the stationarity and simplex order of sample series, and prepares for cointegration test. See table 1 for the test results.

From the table 1, it can be seen that the original time series data and the first-order differential sequence are unstable even at the significance level of 10%, while the second-order differential sequence is stable at the significance level of 1%. Therefore, the original time series is second-order unitary, and there may be a co-integration relationship between them.

2. Co-integration test of sample data. The unit root test shows that China's trade surplus with the United States and the exchange rate of RMB against the US dollar are both second-order, and they may have a stable linear combination. Because of D(COFB, 2)-I(2) and D(EXRA, 2)-I(2), the cointegration regression model is:

D(COFB，2)= α+βD(EXRA，2)+ε

The equation of each parameter is estimated by least square method;

D(COFB，2)=- 1.026596+4 1.45292 * D(EXRA，2)

(-0.2579 16) (0.2253 16)

R2 = 0.00 1877 F = 0.050767 DW = 3.3 12722

From the above regression results, we can see that there is no long-term equilibrium relationship between them, let alone causality. The test results are far from the policy expectations of China and the United States, and also far from the traditional economic theory. Therefore, the American government and people should not expect to improve the trade situation through exchange rate regulation, but should adhere to the essence of trade liberalization, abandon the wrong practice of demanding RMB appreciation by creating trade frictions, and treat the trade deficit rationally. Otherwise, any protectionist measures will harm the well-being of the two peoples. Because two basic points fundamentally determine the inevitability of the existence of Sino-US trade surplus now and even in the future:

First, there are great differences between China and the United States in industrial structure and economic structure. The United States has shifted from low-end manufacturing to capital-intensive industries in the mid-1980s, while China is still a country where labor-intensive industries are concentrated. In addition, the economic structure of the United States is dominated by household consumption, and China is a big exporter of labor-intensive consumer goods. In recent years, China has been the largest supplier of toys and sporting goods imported by the United States, and replaced Japan as the largest source of electronic consumer goods imported by the United States. This pattern will not change in the next few years.

Second, the industrial gradient and supply chain changes in Asia have made China the main origin of Asian exports to the United States. After the reform and opening up, Japanese and Korean enterprises increased their investment in China due to the advantage of labor cost in Chinese mainland, and processing trade gradually became the main trade mode in Chinese mainland. Subsequently, Chinese mainland's trade deficit with South Korea and Japan began to expand, and its trade surplus with the United States and Europe began to grow. Therefore, a large part of China's trade surplus with the United States is actually a substitute for other Asian economies' trade surpluses with the United States.

An analysis of the reasons why the United States demands RMB appreciation

The empirical results of this paper also prove that there is no causal relationship between exchange rate and trade surplus, but why does the US authorities directly target the RMB exchange rate when facing the problem of expanding trade deficit? This paper holds that the underlying reason is that China should share the cost of dollar depreciation from the perspective of economic security and political security, thus preventing China's economic rise. However, this deep-seated reason has been concealed under a superficial excuse: the essence of reducing the US-China trade deficit is trade protectionism. The changing track of American foreign trade policy after World War II can prove this point. Due to the limited space, this paper only analyzes the superficial excuses and essence.

The trade deficit has always been an indicator of American foreign economic policy. 197 1 year, the first trade deficit of the United States since 1893 was $2.024 billion. In August of that year, the Nixon administration immediately announced that it would increase the import surcharge by 10%. In June 5438+February of the same year, according to the Smithsonian Agreement, the Group of Ten adjusted its exchange rate against the US dollar, with Japan and the United States having the largest surplus and the largest currency appreciation, rising from 1 US dollar to 308 yen. However, these measures failed to prevent the increase of the US trade deficit, which reached $6.44 billion in 1972. In February of that year, the United States once again announced the depreciation of the dollar, and the yen appreciated to 1 dollar against 256 yen. The trade deficit between the United States and Japan surged to $36.8 billion at 1984. Since then, the US-Japan trade has been filled with smoke, and the pressure of yen appreciation has been increasing, reaching 1: 150 when louvre accord signed it. Japan took this as a turning point and entered the era of bubble economy.

Very similar to the US-Japan trade situation in those years, American manufacturing, textile and other interest groups now believe that the main reason for the widening US-China trade deficit is that China underestimated the RMB exchange rate, and demand that the US government take a tough attitude towards China on the RMB exchange rate issue. Creating trade disputes is one of the main means for the US authorities to demand RMB appreciation. According to the statistics of the United States International Trade Commission, in 2006, from 1980 to 10, the anti-dumping investigation initiated by the United States against China was from11,mainly after China's accession to the WTO. Only after China's accession to the WTO, the United States conducted six investigations on China's safeguard measures in accordance with Article 42 1. In addition, on March 30, 2007, the US Department of Commerce decided to levy countervailing duty on coated paper from China, which indicated that the US countervailing policy towards China had changed greatly. There is no doubt that China has become the scapegoat for the American economic depression. They used the US-China trade deficit as an excuse to create various economic frictions and put pressure on the China government to appreciate through various channels. Its essence is pure trade protectionism.