At present, the research on hydraulic power chuck in our country is relatively backward, especially the lack of research on mechanics characteristics seriously affects the improvement of clamping force and transmission accuracy of chuck, which seriously restricts the development of CNC machine tools in our country. Therefore, the research on mechanics characteristics of the hydraulic power chuck is imminent. The method based on ANSYS software was presented to analyze the mechanics characteristics of the hydraulic power chuck. The contact methods of the wedgecore sleeve, disc body, slide and workpiece were defined, the bolt links were simulated, and under the working load, the stress and displacement of the chuck were analyzed. It lays foundation for failure analysis. In addition, the clamping force was analyzed by ANSYS. The analysis results were compared with the test results and theoretical calculations to verify the correctness of the proposed analytical method of mechanics characteristics.