Abstract: In order to improve laser drilling velocity and the utilization of laser energy, the optimal matching parameters of the combined laser drilling were studied by means of space superposition drilling by long-pulse laser and short-pulse laser. The optimal matching model of the combined laser drilling was established. Based on the balance of generation and expulsion of the melted metal, the optimal parameters of long-pulse laser and short-pulse laser, and the combined laser drilling velocity at the optimum matching point were obtained theoretically. The combined laser drilling of stainless steel with the thickness of 5mm was performed with ms and ns pulse Nd:YAG lasers. The experimental results show that in the case of the optimum matching, the combined laser drilling velocity is 3.3 times higher than that of the ms pulse laser alone. Both theory and experiments indicate that the maximum drilling velocity can be obtained at the optimum matching point, and laser energy is fully utilized.