In order to solve the problem that the aperture of the small hole part is too small and the irregular shape of the surface is difficult to be processed. A solid - liquid two - phase abrasive grain polishing method is proposed. Based on the standard model and SIMPLEC algorithm, the numerical simulation of the surface of the micro – holes were carried out under different inlet speed conditions. The change of the turbulence kinetic energy, dynamic pressure and turbulence intensity of the micro – holes flow channel with the inlet velocity is discussed. The quality control law of the inlet velocity on the sol-id-liquid two-phase abrasive flow polishing. In order to verify the accuracy of the numerical analysis, the necessary solid-liquid two-phase flow polishing test was carried out with the micro-hole parts. The surface roughness of the inner surface of the micro-holes before and after polishing was tested. The results show that the surface roughness is reduced from 1.702 before polishing to 0.303 after polishing. The solid - liquid two - phase abrasive flow machining can effectively improve the surface quality of micro – holes.