The equilibrium of aggregate social supply and aggregate social demand is the theoretical foundation and the basic goal of macroeconomic regulation and control. The Theory of the equilibrium of aggregate supply and demand in macroeconomics in the West mainly deals with the problems of total equilibrium and price equilibrium, but always neglects structural equilibrium and material equilibrium. This is the defects of the Western economic theoris. Karl Marx's theory concerning the reproduction of the aggregate social Capital, which expounds the laws of the macroeconomic equilibrium and the macroeconomic movement, essentially is fundamentals of macroeconomics. Karl Marx's theories concerning the equilibrium of aggregate social supply and aggregate social demand that include total equilibrium, structure equilibrium, material equilibrium and price equilibrium are the theoretical foundation of macroeconomic regulation and control. The use of the machanism of macroeconomic regulation and control is that the government uses all kinds of economic levers to regulate and control the national economy. And so the main problem of the use of the mechanism of macroeconomic regulation and Control is to correctly deal with the relation between the government's regulation and control and the market mechanism. In view of the macroeconomic situation in China at present, to choose the pattern that the economy as a whole is regulated and controlled by "hard" government and "soft" market is not only entirely appropriate for the status quo but also absolutely necessary.