For the conglomerate layer, the tooth shape optimization and preliminary tooth layout design of PDC bit are carried out. The single tooth rock breaking experiment of ordinary plane tooth, conical tooth and axe tooth is carried out in the conglomerate rock sample, and then the optimized axe tooth is simulated and analyzed to optimize the optimal tooth surface angle of axe tooth, and then the cutting simulation is carried out with ordinary plane tooth to verify the experimental results. The results show that the axe tooth has the highest cutting efficiency and the most stable stress in the conglomerate layer; The drilling effect of 140 ° axe tooth in conglomerate is better; The cutting efficiency is the highest when 140 ° axe teeth are matched with 30 ° caster angle.