Polycrystalline diamond compact （PDC） has been widely used in geological exploration and oil drilling industries due to its significant advantages such as high hardness， high elastic modulus， high thermal conductivity， isotropy and good wear resistance. In recent years， with the increasing exploitation of deep and ultra-deep wells， PDC has been applied to the drive shaft of screw drills. In this paper， the PDC thrust bearing on the drive shaft of screw drill is taken as the research object. From the perspective of statics and the manufacture process of PDC bearing， the finite element analysis of SolidWorks Simulation software is used to explore the failure modes of PDC thrust bearing under different static pressure， temperature， torque and weld width. The variance analysis of the simulation results shows that temperature， torque and weld width have significant effects on the failure of PDC thrust bearing. Among them， temperature has a high significant effect on the deformation of PDC thrust bearing in three directions. Torque has a significant effect on the deformation of bearing in x and y directions. Weld width has a significant effect on the deformation of bearing in x and z directions.