Abstract: A fast rough EHL point contact method considering dynamic change of roughness has been established to study the rougness effect in EHL point contact. Qualitative and quantitative analysis then was carried out to discuss the influences of load, speed, slip ratio and RMS roughness on the maximum contact stress and minimum film thickness. The results showed that, surface roughness changed the shape of pressure distribution and film thickness. In general, the maximum contact pressure was increased and the minimum film thickness was reduced comparing with results under smooth condition. The effect of surface roughness on film thickness was more significant under low load condition. The influence of roughness at different velocities was basically the same and shows a linear trend of change. The film thickness ratio increased firstly and then decreased with the increase of load, and reached its peak at about 25 N.