In this paper, diamond turning of monocrystalline silicon under laser-assisted conditions is taken as the object, the temperature field model of laser-assisted heating is established, and the temperature field distribution of monocrystalline silicon surface and sub-surface is simulated by COMSOL software. The experimental results of temperature measurement and temperature field simulation of monocrystalline silicon with laser assisted heating were compared and verified. Finally, the experiments of laser-assisted diamond turning with monocrystal silicon were carried out to study the effects of laser power and spindle speed on cutting force, surface roughness, chip morphology and tool wear under the conditions of constant feed and backdraft. The results show that the surface temperature reaches the brittle-plastic transition temperature when the spindle speed is 2 000 r/min, the laser power is 32-40 W, and the sub-surface heat transfer depth exceeds 6.8 μm above 500 ℃. The effect of laser softening materials is affected by both power and spindle speed. With the increase of laser power and the decrease of spindle speed, the machining performance and surface quality of monocrystalline silicon are improved and tool wear is reduced. However, the surface roughness of monocrystalline silicon increases greatly due to the thermal damage caused by laser power up to 48 W. The minimum surface roughness of monocrystal silicon can reach 3 nm under the conditions of 40 W laser power and 2 000 r/min spindle speed.