Surface roughness affects the friction behaviour, stress distribution and surface quality; moreover this influence is more significant when scaling down the strip size. A novel approach has been proposed to investigate the surface roughness in asymmetric rolling based on Finite Element Analysis (FEA). Evolution of asperity flattening, contact area ratio and surface roughness is investigated under various simulation rolling conditions. The model reviewed numerical solutions for real surfaces with asperities of arbitrary shape and varying size and height distributions. The rolling characterization has also been identified for asymmetric rolling. The difference of change in surface roughness for upper and lower strip surface is large during rolling. The effect of the speed asymmetry factor on strip bending has been established. An increase of the speed asymmetry factor causes an increase in the strip curvature, while the force parameters decrease with increasing asymmetry factor. The speed asymmetric factor influences the strip bending significantly. It is the first attempt to carry out this kind of research in surface roughness based on real surface during asymmetric rolling of thin strip. 2013 Elsevier B.V.