The labor theory of value was first put forward in modern times, and the surplus value was studied in the form of land rent. BuaGilbert is the founder of French classical political economy and the pioneer of physiocratic school. His economic works include Details and Supplement of France (1695, 1707), The Nature of Wealth, Money and Taxation (1705), The Theory of Cereals, The Defence of France (1707) and so on. He resolutely attacked the mercantilist policy and proposed that agriculture was the source of wealth creation. He is also the original founder of labor value theory and an enthusiastic advocate of free competition. However, Petty and BuaGilbert have not yet formed a complete theoretical system. From Petty to1mid-8th century, it was an important stage of the gradual rise of British classical political economy, and some important economists appeared. Petty's direct heirs are Locke and North. Locke's major economic works include On Government (1680 ~ 1690) and On the Consequences of Reducing Interest and Increasing Monetary Value (169 1). He used "natural law" to demonstrate the boundaries of ownership, and thought that land rent and interest were the result of uneven distribution of land and money. North's main economic work is Trade Theory: mainly on interest, coin casting and breakage, and currency inflation (169 1). He put forward a clear concept of capital for the first time, and also affirmed the rationality of charging interest. Marcy and Hume were important economists in the first half of18th century. 1750, Marcy published The Reasons for Determining Natural Interest Rate. He studied profit earlier, classified interest as a part of profit, and thought that interest rate was determined by general profit rate.