In the drilling process of deep formation in Bozhong block, there is a mismatch between the existing drill bit and the formation, which leads to early failure. The impact energy utilization rate of the drill bit to the composite impact tool is insufficient, and the performance of the tool is not fully utilized. The mineral composition analysis and anti-drilling experiments were carried out for the rocks of the deep medium-hard strata in the Bozhong block. Combined with the acoustic time difference logging data, the anti-drilling characteristic profile of the whole well section was constructed. The composite cutting model of polycrystalline diamond compact(PDC) single tooth-rock interaction was established by using finite element simulation software, and the rock crushing performance of different PDC teeth under composite impact condition was analyzed. It is found that the combination of conical teeth and conventional teeth has the best cutting effect on rock under composite impact. A composite impact tool supporting drill bit suitable for medium-hard ground was optimized and designed. A numerical simulation model of full-bit composite impact rock breaking was established to analyze the characteristics of rock breaking during composite impact drilling. The simulation results show that the volume of broken rock increases under the action of tensile stress, and the contact between the drill bit and the rock is more stable, which effectively reduces the jump drilling phenomenon and significantly improves the mechanical drilling speed.