The determination mechanism of pension benefits is one of the core contents of the public pension system. This paper systematically studies the determination mechanism of social security retirement benefits in the United States from three aspects: 1) in terms of retirement age, the relative separation of labor relations and social security relations has been realized, and an initial pension adjustment mechanism has been established according to the schedule of“benefit reduction for early retirement and benefit increase for delayed retirement”through the introduction of “full retirement age”; 2) in terms of benefits calculation, it used national unified the calculation method of primary insurance amount ( PIA) based on individuals, and used hierarchical empowerment methods for income redistribution and poverty reduction for the elderly;3) in terms of benefits adjustment, it established the index automatic adjustment mechanism of retirement benefits based on the cost-of-living adjustment(COLA).Based on the actual situation of China and the experiences of American retirement benefits system, this paper holds that the reform direction of the basic endowment insurance in China is to introduce flexible retirement policy, link the pension calculation with the national indicators to promote the national overall planning and institutional equity, enhance the incentive effect of the pension calculation on the insured and payment behavior, and establish a scientific and reasonable benifits adjustment mechanism as soon as possible．
