The paper investigates A. Stoianov’s views on the theoretical and methodological problems of comparative history of law as well as the results of comparative-historical research. It is explained that the scientific views of the scientist were influenced by the ideas of the historical school of law and sociological positivism. It is proved that the comparative history of law was consistent with the general history of positive law, which was to deal with theoretical problems of historical jurisprudence. A. Stoianov substantiates the idea of a rational and heuristic integration in the comparative history of law of such important areas of historical and legal reality as dogmatic, philosophical, and historical. It is proved that the positive law of various nations as a sociocultural phenomenon was seen in terms of constant, consistent and progressive evolution to define and formulate universal laws of development and co-existence. It is revealed that the basis of the methodology was the comparative historical and comparative ethnographic methods. Based on the study and comparison of the law among the peoples of different continents and epochs A. Stoianov emphasized the stage concept of law in which the stages of legal development were attributed to cultural and value aspects, regardless of the spatial and temporal dimensions. The scientist argued that all nations passed the initial stages of legal development. The conductive chain between the law of the primitive period and original civilizations was the law of the ancient East, which explained the evolution of law in the countries of Western Europe.