Abstract: Social security and public services such as education, medical care, elderly care, etc. are the essential parts of modern economy system, and important factors of modern national governance. This paper has summarized two logic clues through the evolution of the social security and public services provision system in the past seventy years since the construction of People's Republic of China:one clue is the "socialization process" of social security and public services provision system because the bureaucratized social security and public services provision affiliated to workshops and government units have become an independent policy system with the people freeing themselves apart from their workshops in the marketing economic system; the other is the integration of rural and urban social security systems in to one system and the equalization of public services provision among all the nation. Social security system and public services provision system with Chinese characteristics, covering all the people nationwide based on the principle of sustainability, have been gradually formed along with the two evolution clues since the era of opening up and reform in late 1970s. It concludes that after the 18th National Congress of CPC, the social security and public services provision system are facing new challenges of ill-balance and ill-sufficiency in fast economic growth and move into the new stage to realize the balanced and sufficient development.