In recent years, China clearly puts forward that it will build three pillar endowment insurance system, including the basic pension insurance, enterprise supplementary pension insurance and personal savings insurance. However, in terms of current situation of China’s endowment insurance, the basic pension insurance is still a major component, and pension replacement rates are declining and below the international minimum standard (ILO, 55%), lack of long-term sustainability, and the adequacy of the pension insurance system is worrying. This paper, based on the analysis of the adequacy of pension assets in China, found that at present, the pension assets of urban residents in China, especially in the net pension assets, the basic old-age insurance plays an important role. And as the second pillar and the third pillar of the enterprise supplementary pension insurance and personal savings insurance, the ratio is relatively low. And in the composition of China’s urban residents’assets, the ratio of personal savings and other assets accounted were more than 20%, which means on the job personnel accumulated a certain scale of wealth, the third pillar of personal savings insurance still has great development space, to be supported by the national policy to guide and cultivate the capital market. In this paper, and a variety of measures should be taken to guarantee the sustainability of basic endowment insurance to build a multi-pillar pension system in the future.