1, new democratic society-transitional period: this period is from 1949 to 10- 1956, which is a period of transition or transformation from new democratic society to socialist society. Including establishing a new China, consolidating the new regime, restoring the national economy and socialist transformation. The social form of this period is a new democratic society. Since its founding, People's Republic of China (PRC) has experienced two historic changes: from semi-colonial and semi-feudal social form to new democratic social form, and from new democratic social form to socialist social form.

2. The tortuous period of socialist construction (1end of 956-1May of 966): Also known as the period of starting to build socialism in an all-round way, the theme is to explore the road of socialist modernization in China. However, due to subjective and objective reasons, it presents the stage characteristics of tortuous development.

3. Ten years of turmoil during the Cultural Revolution (1May 1966-19761October).

4. New period of socialist modernization (1978 till now): The basic content and feature of the new period is to build socialism with China characteristics. Including the great turning point year, reform and opening up, and continuous exploration.