Abstract: Owing to the hardness and brittleness of single-crystal Si, brittle fracture and tool wear can occur easily during conventional single-point diamond turning (SPDT). Based on finite-element simulation analysis and orthogonal experiment methods, in this study, we investigated the influence of laser parameters on the temperature field of single-crystal Si using the Gaussian three-dimensional model and evaluated the advantages of laser-assisted turning using the temperature field model. The results showed that the influence weights of the spindle speed, feed rate, back cut rate, and laser power on the surface roughness Ra of single-crystal Si were 17.23%, 33.53%, 10.60%, and 7.43% respectively. The optimal processing parameters were—spindle speed of 4000 r/min, feed rate of 2 mm/min, back cutting rate of 5 μm, and laser power of 3 W. The final experimental verification results showed that compared to conventional processing technology, using laser-assisted process parameters increased the product qualification rate by 66.7% and improved the surface roughness of the parts by 13.3%. These results collectively verified the superiority of laser-assisted processing.