Abstract: Commercial PLA filament was used as a fused deposition modeling (FDM) 3D printing material, and its tensile strength and notched impact strength were taken as optimization indexes to design orthogonal tests. The PLA parts were fabricated with an FDM printer, and the effect of layer thickness, printing speed, nozzle temperature and filling angle on the mechanical performance of the resulting parts were investigated by an orthogonal analysis method. By means of the comprehensive scoring method and comprehensive balance methods, the optimal printing process parameters were obtained and the correctness of the test results was verified. The results indicated that the mechanical properties of 3D-printed parts were optimum when the layer thickness is 0.3 mm, the printing speed is 90 mm/s, the nozzle temperature is 220 ℃, and the filling angle is 45 °/45 °.