The cone bit is the most principal rock breaking tool in drilling engineering.The statistical analysis of field data shows that the early damage and failure of sliding bearing is one of the main reasons that affect the service life and performance of the cone bit kt196 torque converter in the real drilling process.Aiming at the complex working environment of cone bit sliding bearing with heavy load, high temperature and mixed lubrication, the paper establishes a multilevel line contact model of rough surface and carries out simply southern cat shirt the finite element modeling and analysis from the perspective of contact mechanics.Then the Von Mises stress, Residual normal deformation and Inelastic dissipated energy are obtained under the different cycles of loading-unloading.The results show that with the increase of cycles of loading-unloading, the part of edge area of the line contact enters into elastic shakedown and the asperities in the central area occur irreversible plastic deformation, which has a significant influence on the stability of the sliding bearing of the cone bit.