This paper studies the effect of abrasives size on machined workpiece surface in solid abrasives lapping. From the results it can be seen that the value of roughness of the machined workpiece surface increases as the size of abrasives increases. Its principle is same as ultraprecision grinding and tradition lapping. But for same size abrasives, the results got in this paper is better than them in ultraprecision grinding and tradition lapping. In this paper, the roughness of machined workpiece surface can reach Ra2.83 nm, by using the abrasives which size is 3.5μm.