Abstract: Friction lubrication theory, fluid mechanics theory and rolling theory were integrated to establish mechanical model considering multi-factor coupling rolling interface in unsteady lubrication process of dynamic roll gap. Interfacial films constraints were integrated to constitute multi-factor coupling model based on the unsteady lubrication process interface friction model, the work roller movement model and the roll gap stress distribution model. A systematic analysis of the corresponding distribution of the pressure stress and friction stress of work zone at different time was made when the reduction rate and the surface roughness value were fixed during unsteady lubrication. At a certain reduction the influence of surface roughness and back tension stress on the pressure stress and friction stress in the work zone was also analyzed. Results indicate that under the condition of larger back tension stress when the reduction rate and the surface roughness value were fixed the pressure stress and friction stress was low. The pressure stress gradient and friction stress gradient were quite small at the same time. The friction stress got the maximum in the edge of inlet and outlet, the pressure stress and friction stress of roll gap increased when the back tension stress decreased. The pressure stress gradient and friction stress gradient were larger when the reduction rate and the surface roughness value were variable. When the back tension stress was large, the influence of surface roughness on the pressure stress and friction stress in the work zone was very large, the pressure stress and friction stress of roll gap increased with the surface roughness, when the back tension stress was small, the influence of surface roughness on the pressure stress and friction stress in the work zone was obvious.