After entering the aging society, OECD countries' government pension replacement rate has begun to decrease and the demand for old—age additional pension is increasing. Then, a development strategy of national pension system is forming: “ consolidating government pension, stabilizing employer's pension and developing personal pension” . To balance the risks of a single pension scheme and to maintain the adequacy of the pension appropriately, the development strategy of national pension system is one of active ageing initiatives to foster the consumption capacity of the aging population. A retrospective study on the reform of pension system mechanism in typical countries shows that, the national pension under different welfare models is different at the beginning of the establishment, and the development path is not the same, but the development trend of the institutional mechanism is consistent. According to the timetable of social development of the aged, China should improve the pension system by coordinating central basic pension, promoting the development of employer's pension and cultivating personal pension to build the national pension system and achieve the innovation of management system and institutional mechanism.