PIP: Since the founding of the People's Republic of China, the development of the population theory has experienced some setbacks. It is important to learn lessons from the past and establish a socialist population theory based on science. During the 1st 30 years of the People's Republic of China, the development of a population theory can be divided into 3 stages: 1) stage one was from 1949 to 1957 -- belief in population control on the basis of sociology; 2) stage two was from the late 1950s to early 1960s -- represented by Mr. Ma Yinchu's "New Population Theory" and the theory of the opposing side; and 3) stage Three began after the 1960s. Throughout the 1960s, studies of population theory remained stagnant, and no progress in this field was possible. In the 1970s, especially since the downfall of the "Gang of Four," the development of a population theory has entered a new stage. 3 problems with the development of the population theory discussed by the author are: 1) an evaluation of Comrade Mao Zedong's thoughts on population, 2) the division of different schools in population theory, 3) the different periods in the development of the population theory since 1949. Mao Zedong did change his thoughts on population control, but he was in favor of family planning and supported studies in population theory. Besides Ma Yinchu, Chin Da, Fei Xiaotong, Wu Jingchao and others also had their own population theories. The author emphasizes the contributions made by Mao Zedong and the Communist Party in the development of a population theory. New accomplishments and experience are expected with the downfall of the "Gang of Four."