The typical experiment apparatus of rock friction sliding was designed and improved. Under low normal stress

the static friction coefficients for 8 silicate rocks were studied experimentally based on the apparatus. The surface topography of the sliding surface was characterized by the statistic parameters and asperity; and the influence of roughness parameter on static friction coefficient was analyzed. When the sliding surfaces are polished

the static friction coefficients of phyllite

quartzite

lithic sandstone

and quartz sandstone are 0.38-0.47; and the ones of conglomerate

gravelly coarse quartz sandstone

medium grained lithic sandstone

and medium grained quartz sandstone are 0.83-1.07. The two roughness parameters which are the maximum depth of profile valley (Rm) and the maximum height of profile peak (Rp) make the asperity produce different actions and induce to different static friction coefficients. With the increment of the two roughness parameters

the static friction coefficient is increased with exponential law. The amounts of asperity are less on the sliding surfaces of phyllite

quartzite

lithic sandstone

and quartz sandstone. The amounts are more on the ones of conglomerate

gravelly coarse quartz sandstone

medium grained lithic sandstone

and medium grained quartz sandstone. With the increment of asperity amounts

the static friction coefficient is increased during rock frictional sliding.