Abstract: By using 3 D surface topographical measurement,the topographical features of dry sliding surface of compacted graphite cast irons(C G irons) were investigated. The experimental results indicate that the surfaces are characteristic of pit peak like and groove ridge as well as combined topography. For the groove ridge surface, the sliding surface height has a very large range in the direction perpendicular to the sliding surface and the surface height distribution is asymmetric. For the pit peak surface, the surface height distribution range is very small and its surface height also has asymmetric distribution. For the combined topographical surface, the surface height distribution is symmetric and its range medium. In view of the effects of surface topographical characteristics on the tribological properties, it is suggested that surface height distribution range and void volume ratio are the two most important factors which influence the efficiency of frictional heat transfer to far end of the contacting zones, thereby,the surface with pit peak topography presents the highest frictional coefficient and wear resistance, and the surface with groove ridge topography presents the lowest frictional coefficient and wear resistance.