Qin Banqian was the earliest unified currency in the history of China, and its emergence and development had an important impact on the development of later currencies. In 22 1 BC, Qin abolished the currency of the Warring States at the end of the Warring States Period. On this basis, Qin improved the old currency of the six countries, and stipulated that the semi-circular square was the national currency, ending the chaotic state of China's ancient currencies with different shapes and different weights. Since then, Qin Banqian, as the earliest unified currency in China, has begun to appear on the historical stage. Through the study of Qin Banqian, this paper tries to reveal the development of Qin Banqian and its important influence on the history of ancient currency development in China from two aspects. First of all, the emergence and development of semi-two currencies declined and eventually withdrew from the historical stage. course