Social security contract is a social contract reached by promoting stable development of the society for providing risk protection of citizens to maintain social fairness by different behavior main bodies in the same society based on consultative consensus. In modern national governance system, social security is the co-governance field participated by multi-subject such as government, enterprises, social organizations and individual citizen, therefore, the division and practice of social security responsibility become the key to “the establishment and the keeping of contracts”. Currently, China’s social security contract stays at the perfecting period of “the establishment of the contract”, the division and practice of social security responsibility of multi-subject are not clarified and improper, as a result, the social security system covering all citizens needs to be perfected by the contract governance through the coordination of the “establishment” and the “keeping”. China should bring into fully play the institutional advantages of the socialism with Chinese characteristics, continue to perfect social security institution system, strengthen legal construction, enlarge contract spirit, promote the willingness and ability to take the social security responsibility of each responsibility subject, boost the related main bodies to actively take the responsibility based on the contract, use the efficient and reasonable mechanism with the shared responsibility and shared interests to boost co-construction, co-governance and co-sharing by multiple responsibility subjects, and build social security community with “everyone having the responsibility, everyone taking the responsibility and everyone enjoying the social security”.