Abstract: In view of the fact that the surface quality and dimensional accuracy of laser selective melting Inconel 718 formed parts are difficult to meet the requirements of precision parts. Firstly, the influence of different milling parameters (milling speed v_c, milling depth a_p, milling width a_e, feed per tooth f_z) on the cutting force (F) and surface roughness (Ra) is analyzed through the milling and cutting post-processing process.Then, based on the grey relation analysismethod, the multi-objective was transformed into a single objective optimization of grey relation(GR), the second-order GR regression prediction model was established by the stepwise regression method, and finally the particle swarm optimization was used to obtain the optimal parameter combination. The results show that the importance of the influence on F is f_z, v_c, a_p and a_e, the importance of the influence on Ra is f_z, a_p, v_c and a_e respectively, and the maximum decrease of Ra is 97.80% and the average decrease is 94.03% after milling. The maximum error of the established prediction model is not more than 5%; The optimal solution of GR is 0.8173, and the corresponding optimal milling process parameter combination is v_c=46.96 m/min, a_p=0.25 mm, a_e=2.90 mm, f_z=0.025 mm/z.