At present, the problem of history of the State policy for the promotion of science is of interest to many scientists. However, the features of the origin and formation of the domestic legislation in the sphere of popular scientific knowledge promotion through libraries are not enough studied. The purpose of the study was to identify and analyze the most significant legal documents in the field of science and technology popularization, including those addressed to libraries. The source base was an amount of legislative acts from 1917 to 1941. As the result of the study, the author determined that the development of the domestic system of the State regulation of popularization of science began in the early years the Soviet state existence. The dissemination of scientific knowledge into the society through the system of non-formal education was regarded as the necessary means of awakening the activity of masses in the process of their participation in the Cultural Revolution, as well as the restoration and construction of the national and agricultural economy. Normative legal acts concerning libraries were developed in accordance with the national policy of the party and the government. The legislative authority charged libraries to participate in the propaganda of natural, technical, and agricultural knowledge, and to promote self-education of all citizens. The official documents of the given period recorded specific forms and methods of science popularization, including: acquisition of collections of popular science literature, preparation of lists of recommended publications, organization of traveling exhibitions, creation of scientific circles, conducting loud readings and excursions, participation in cultural and library trips, etc. The data obtained in the course of the study confirmed our assumption that in addition to serving the ideological order of the State, the librarianship in the USSR was legally entrusted with the functions of popularization of general scientific knowledge already in the early Soviet period.