Abstract: Using the theory of life table,we establish the actuarial model of contributing rate under pay-as-you-go system,and analyze the potential crisis based on the coming of old age population.According to the concrete condition in China,we derive the actuarial model of contributing rate under the social plan as a whole and the individual account system by using life annuity theory,and finally present a practical example of individual account in this paper.

Key words: pay-as-you-go system, partially accumulated system, life annuity, actuarial present value, defined benefit scheme, defined contribution scheme