Abstract: The laser-silicon interaction process was investigated with the superposed radiation of two pulsed lasers. A pulse duration of 1ms was superposed by 7ns pulses, creating a combined pulse laser (CPL). The experimental study of single millisecond pulse laser and CPL irradiation on silicon wafer was carried out, respectively. Along with numerical calculation, the surface damage morphology caused by the two laser operation modes was compared. It can be divided into three kinds according to different delays of CPL. Further research was done on the melting depth and damage radius. The results show that the damage effect induced by CPL is more severe, including cleavage cracks, ablation and fold. The damage radius on the surface mainly depends on the energy density of incident ms laser, and the melting depth decreases with the increase of delay time. The better damage effect of CPL is ascribed to the pre-heating ms laser and the interaction of the follow-up ms laser with the surface damage formed by the ns laser. The results can be used as a reference for the processing of semiconductor materials by combined pulse laser in the future.