Abstract: The dry friction and wear tests were carried out on the SA508 Gr.3 Cl.1 steel with different surface roughness (0.319, 0.451, 1.210, 2.300, 5.240 μm) by using the rotating steel ringfixed graphite ring end face friction pair structure. The effect of the test steel surface roughness on the friction and wear properties of friction pairs was studied, and the wear mechanism was analyzed. The results show that with the increase of the surface roughness of the test steel, the friction coefficient decreased first and then increased, reaching the smallest value when the surface roughness was 0.451 μm and the largest value when the surface roughness was 5.240 μm. The friction and wear mass loss of the graphite increased basically with the increase of the surface roughness, and the wear mechanism was mainly abrasive wear. When the surface roughness was relatively low, a large area smooth graphite transfer film was formed on the wear surface of the test steel, and the carbon content in the film was relatively high. When the surface roughness was relatively high, the furrow effect was formed, and the area of the graphite transfer film and the carbon content in the film were relatively small.