Abstract: Hydraulic fixtures are commonly used as fixtures for tensile testing, but there is a slight lack of systematic research on the optimization design of their jaws. In this paper, a finite element analysis model for the jaws of hydraulic wedge-shaped fixtures was established based on ANSYS. Based on actual working conditions, boundary conditions were set for finite element analysis and calculation. After parametric modeling of various sizes of hydraulic jaws, orthogonal experiments were conducted to select parameter values that are highly correlated with the target through correlation analysis. The results show that, according to the parametric modeling and analysis of the jaws in hydraulic wedge-shaped fixtures, the variables with greater sensitivity are the wall thickness of the oil cavity, the opening width of the lower end of the jaw, the depth of the wedge surface, and the angle between the two wedge surfaces. Orthogonal test and range analysis were used to optimize the filtered variables, and then according to the orthogonal test results, the final optimization scheme for hydraulic jaws was determined and simulation check was carried out. Finally, the weight is reduced by 20.29%, the overall stiffness increases by 12.92%, and the directional stiffness (x-axis) increases by 10.82%.