1. The theory of western economics has gradually evolved into modern microeconomics and macroeconomics through the development of mercantilism, classical economics and vulgar economics. We generally call it western economics, which directly comes from the micro-theory founded by Marshall and the macro-theory founded by Keynes.

2. Microeconomics has been supplemented many times since Marshall put forward it. Due to the formation of monopoly at the end of 19 and the beginning of the 20th century, the original micro-theory based on perfectly competitive market types was challenged, so in 1933, Robinson of Britain and Chamberlain of America put forward the theory of imperfect competition and monopoly competition, which filled a big loophole in micro-research. In addition, Hicks, Walras and Pareto put forward the general equilibrium theory, ordinal utility theory and welfare economics after 1930, which further supplemented the traditional microeconomic theory system.

3. After World War II, American economists represented by Samuelson integrated micro-theory and macro-theory, forming the mainstream ideology of modern western economics. With the change of historical conditions, they constantly change their views, which shows the evolutionary nature of the theory, and the theory always develops with the change of economic reality.