A computational model of the heating and ablation of semiconductor materials under repetitive laser pulses is described. By finite element method, the front and rear surfaces’ temperature increase and ablation depth of two semiconductor materials (Si and Ge) under repetitive laser pulses of different duty ratios are computed and analyzed, the influences of material thickness being studied. The numerical results show that under repetitive laser pulses radiation, the front surface temperature increase of semiconductors, like metals, presents a typical tooth-like profile; while the rear surface temperature increases in a step-by-step manner, which is different from that of metals. Also, repetitive laser pulses have more efficiency for heating and ablation on semiconductors than the CW laser.