When the trapezoidal lead screw pair works normally,the deformation of the contact surface between the lead screw and the nut causes uneven distribution of the gap oil film thickness and pressure,which leads to a series of influences on the working state,oil film lubrication characteristics and bearing capacity of the trapezoidal lead screw pair.Therefore,the fluid-structure interaction analysis method was used to simulate the oil lubricated trapezoidal lead screw pair.The trapezoidal screw pair solid model and screw nut gap oil film model were established.Using the fluid-structure interaction simulation analysis method,considering the phenomenon that the oil film bearing pressure caused the trapezoidal screw pair structure deformation,the stress and deformation of the screw and nut and the influence of oil film thickness on the bearing performance and the stiffness were gotten under the same conditions and different clearance.The results show that the trapezoidal screw and nut meet the yield strength requirements of the material under high pressure and heavy load conditions;considering the relationship between the clearance of the trapezoidal lead screw pair and the bearing capacity and stiffness of the oil film,the lubrication and bearing performance of the trapezoidal lead screw pair is the best when the clearance is between 0.15 mm and 0.20 mm.