Social insurance is the most important part of the social security system. Therefore, when discussing the history of social insurance, social insurance cannot be separated from social security.

Social insurance refers to the system that the state establishes a social insurance fund through legislation to give necessary material help to workers who participate in labor relations when they lose their ability to work or are unemployed. Social insurance is not for profit.

Social insurance is mainly through raising social insurance funds, coordinating and adjusting social insurance funds within a certain range, and giving necessary help to workers when they encounter labor risks. Social insurance provides basic living security for workers. Workers can enjoy social insurance benefits as long as they meet the conditions for enjoying social insurance, that is, they have established labor relations with employers or paid various social insurance premiums according to regulations. Social insurance is the core content of social security system.

There are two milestones in the history of social security: first, Germany initiated the social security system in Bismarck era; Second, in 1935, the United States established a perfect social security system and institutionalized social security, which had a great impact on the globalization of social security system after World War II.