The article is devoted to the analysis of the classification of the Russian political parties at the beginning of the 20th century in the Soviet historical literature. The fundamentals of the scientific classification of the political parties were based on Lenin's theoretical heritage. Soviet historians singled out 4 groups: landlords', bourgeois, petty-bourgeois and proletarian parties, according to the existed ideas of the main social classes. The vexed questions of the historiography were estimation and gradation of liberal bourgeois parties; first of all there was no unanimity of views concerning the party "Union of October 17". By the end of 1990s the viewpoint of the liberal-conservative character of the right liberal parties prevailed.