As an important system arrangement concerning the interests of all the Chinese people and the construction of harmonious society, social security has playing a more and more important role in China's political, economic and social development. Therefore, it is especially important to have a perfect social security system, which has been gradully established in most countries in the world. Because of the essential role of the system in economic development, social stablity, protection of human rights and realization of social equity, most countries in the world are taking the implementation and improvement of the social security system as one of their basic national policies. In view of the trend of global reform on social security system, it is undoubtedly essential to review and sort out the history and progress of social security system in order to rationally understand and actively promote relevant reform in China.