Abstract: The research object is expert experiment as a method of scientific study and practical perception, and its importance for the formation of a theory of methods of forensic analysis within the general theory of forensics and authenticity of expert’s opinion. The author studies documentation of expert experiment and the problem of the influence of documentation techniques on the experiment results assessment and expert’s opinion. The article deals with the problem of assessment of the results of expert analysis and experiment by investigators and the court, and the specificity of using different forms and techniques of documenting the results of expert experiment. The research methodology is based on materialist dialectics and tre related general methods: formal-logical, comparative-legal, system-structural, statistical methods, generalization of expert practices, etc. The scientific novelty of the research consists in the fact that the present research is considered as a complex research of experiment in judicial expert practice. The aim of the research is to develop theoretical fundamentals which would organize knowledge about this method, and practical recommendations for raising the effectiveness of using its results in the activities of law-enforcement bodies.