A thermo-mechanical coupling model for a flat plane and a rough surface based on 3-D fractal theory was established. The model considered the interaction between asperities, and integrated the heat flux coupling between the sliding surfaces. By using the nonlinear multiphysics field of the ANSYS software, the frictional sliding process of the elastic rough surface and the rigid flat plane (E/R model), and that of the elasto-plastic rough surface and the rigid flat plane (P/R model) were simulated. The frictional temperature, the contact pressure and the contact area under two different deformation characteristic of the rough solid during the sliding process were analyzed. The numerical results from the analysis and simulation showed that the maximum contact temperature of the rough surface rose slowly during the constant sliding. The maximum contact pressure and the contact area fluctuated within a certain range. The contact pressure and the frictional temperature of the elastic contact (E/R model) were larger than those of the elasto-plastic contact (P/R model), but the contact area was much smaller. The results demonstrated that the elasto-plastic deformation of the rough body had significant influence on the result during the thermo-mechanical analysis of the rough solid in the friction. 