Abstract：In order to study the effect of process parameters of microshot peening ( diameter 0. 02 ～ 0. 20 mm) on the depth of the residual compressive stress layer and surface roughness of the target, three non-dimensional relations were deduced under the conditions of single partical impacting by using the dimensional analysis technique, and the relationships between the depth of the residual compressive stress layer, the surface roughness of the target material, the peening dents diameters, and the parameters of material properties of target and micropartical, the diameter and speed of microparticals, were established. In order to solve the undetermined quantities in the dimensionless relationships, 13 groups of samples that were made up by five kinds of targets, two shot peening materials, three shot peening diameters, and three shot peening speeds were simulated by using the ANSYS/LS-DYNA software. According to the simulation results, the unknown quantities in the three dimensionless expressions were solved.