This study uses elastic–plastic contact theory to analyze the effects of surface roughness and sliding speed on thermo-mechanical deformation and frictional heating of elastic–plastic semi-infinite medium in sliding contact with the fractal rough surface. The evolution of deformation in the semi-infinite medium due to multi-scale surface roughness variation was interpreted in terms of temperature rise, contact pressure; normal and von Mises equivalent stresses using the finite element method. The effect of sliding speed on frictional heating and deformation using time change was also analyzed. This study shows that frictional heating is sensitive to fractal dimension, and sliding speed has a strong effect on frictional heating.