Christianization of indigenous peoples of Siberia was of a general nature and was based on a common legal basis during two centuries. Public arrangements of the Soviet power were characterized by a moderate attitude to the mass baptism and toleration to existing religious beliefs of natives. These general aims were corrected by Russian Orthodox Church which structure was realized by it, and narrow departmental interests dictated speeded up Christianization. This article reviews reforms of missionary activity in XVIII – the first quarter of XIX, which aims were transition from the formal baptism to the consolidation of Christianization and Russianization of other peoples. By the example of autochthonous population of the Khakass-Minusinsk territory features of its forms, methods of baptism and quantitative indicators of baptism were analyzed The vested system of missionary activity could not solve political and ideological tasks of assimilation of the indigenous population of Siberia, integration of multi-confessional multilingual social space of Russian Empire and needed radical changes. The source base is presented by documentation and sources of church demographic statistics.