Based on the key indicators of 2009 Japan's public pension ‘fiscal verification and validation', this paper discusses insurance premium rate, changes of payment standard and multiply influences of Japan's public pension, and makes a thorough research in the stability and fairness of Japan' public pension system. On the basis of above analysis, the determination of the pension premium rate should be considered the ratio of serving and retired staff, so that the relative balance of serving staff's disposable incomes and retired staff's pension incomes can be achieved, fiscal balances of Japan's public pension can be maintained, and sustainable development of Japan's public pension system can be ensured. <<