The objective side of a crime as an integral part of the science of criminal law of Russia and Mongolia is constantly in the spotlight. In the context of this topic the Author of the article considers the concept of «encroachment» on the life of a representative of authority in the criminal legislation of the Russian Federation and Mongolia. In connection with the public danger of this crime, additional qualifying features are proposed. Illusions and gaps in the criminal legislation of Mongolia concerning the moment of the end of encroachment on the life of a representative of authority are highlighted. In this issue, we consider it expedient to use the Russian approach to solving this problem. The article gives a comparative analysis of Art. 317 of the Criminal Code of the Russian Federation «Encroachment on the life of a law enforcement officer» and a similar norm of the criminal legislation of Mongolia.