Surface roughness of oxide scale and strip in hot strip rolling has a significant influence on the friction and lubrication conditions. In this paper, the authors present the measured surface roughness of oxide scale and strip by Atomic Force Microscope (AFM) and Surface Profilometer respectively for hot rolled strip on a Hille 100 experimental rolling mill. Based on the friction coefficient determined through a sensor roll on the rolling mill, a 3D rigid visco-plastic finite element simulation was carried out, and the relationship between the surface roughness and friction coefficient was investigated. Results show that the lubrication in hot strip rolling can reduce the rolling load and torque, and the friction coefficient and surface roughness decrease when the rolling speed increases. Calculated results are in good agreement with the experimental values.