Samuelson is the most important representative of the classical comprehensive school and the most famous authoritative figure in western economics today. 1936 graduated from the Economics Department of the University of Chicago, and later worked as a professor in the Economics Department of the Massachusetts Institute of Technology. He was elected president of the American Economic Association and served as an adviser to the American government and financial institutions. 1970 won the Nobel Prize in Economics. The main work is Economics published by 1948, which has been reprinted by 15 times and has become the best-selling economics textbook in history. The theoretical system of this book is first called "Neoclassical School Synthesis" and then "Post-Keynesian Mainstream Economics". Samuelson believes that the contemporary western economy is a mixed economy, and the government is playing an increasingly important role in the economy. In the modern mixed economy, the government plays an important regulatory role by expanding the scale of fiscal expenditure, redistributing national income and directly regulating economic life. Fiscal revenue is an important means and tool for the government to regulate the economy. Samuelson's main tax thought is: (1) tax principle. Samuelson believes that there are two representative tax principles at present: ① interest principle. He believes that fair taxation should make every taxpayer's contribution consistent with the benefits he gets from public services; (2) the principle of sacrifice (redistribution). He believes that people should pay taxes in the ideal way of "sacrifice" so as to make the redistribution of social income "fair and reasonable". The so-called "fairness and rationality" is explained by the law of diminishing marginal utility, that is, the satisfaction brought to a person by increasing 1 yuan is decreasing, so when the tax of 1 yuan is levied on millionaires and given to middle-income or low-income people, the increased utility should be greater than the decrease. Different individual utilities add up to form the total social utility, and social utility can be maximized through taxation. (2) The role of taxation. Samuelson pointed out that taxation is the source of funds for the government to purchase public goods, and it is also an important means to change income distribution. He also emphasized the role of fiscal policy in dealing with depression and inflation. When the economy is depressed and the unemployment rate rises, the government should increase expenditure and reduce taxes to expand demand, increase employment and national income. When there is inflation, the government must reduce social demand by reducing expenditure and increasing, so as to eliminate the price increase caused by excessive inflation. Samuelson pays more attention to tax reduction and advocates bold implementation of "fiscal policy of increasing deficit" on how to use tax to adjust economic policy. It is believed that tax reduction can increase people's disposable income, increase consumption and investment, thus providing more employment opportunities and increasing national income. At the same time, according to the multiplier principle, people's consumption and re-expenditure can create the next round of employment opportunities and income, which can get twice the result with half the effort. As for the government budget deficit caused by tax cuts, it doesn't matter, it just means the expansion of the private sector in the "mixed economy". While reducing taxes, we should solve a large number of illegal tax evasion and legal tax avoidance in reality in order to expand the tax base. He believes that taxation is not only a means used by the government to regulate the economy, but also an automatic "internal stabilizer" installed in the economy. Because corporate tax and personal income tax adopt progressive tax rates, it has the performance of automatic adjustment. When the economy is depressed, the tax amount naturally decreases; In the case of inflation, the tax will automatically increase. These are all in line with the government's intention. However, the role of tax "internal stabilizer" can only buffer the range of economic fluctuations, but can not be completely eliminated. In this way, we need to use "discretionary" fiscal, tax and monetary policies to deal with economic fluctuations. (3) Controlling the fluctuation of economic cycle by changing the tax rate. That is, changing the tax rate according to the economic cycle. When there is a short-term economic recession, the income tax rate can be temporarily lowered to avoid the decline of disposable income, thus avoiding the expansion of the recession. During the period of inflation, disposable income can be reduced by raising the income tax rate, thus reducing the pressure of inflation. However, he also realized that it is difficult to adjust the tax rate, and it needs a long debate in parliament before taking action; In addition, when the recession ends, it is difficult for the tax rate to return to its original level. Samuelson's tax thought is characterized by emphasizing the function and function of tax regulation and control of economic fluctuations. It is advocated that the government should use fiscal expenditure, taxation and other policy means to act on the micro-economy, and that the mixed economy can avoid the most serious consequences of opening higher and leaving lower through appropriate macro-policy adjustment. Samuelson stood on the standpoint of free trade theory and opposed protectionism and tariff collection. He believes that free trade can benefit everyone, while tariffs only benefit the minority groups that have already benefited. In addition, tariff is a progressive sales tax, which will increase commodity prices and ultimately increase the burden on consumers, so it is not advisable to levy tariffs.