Abstract: To investigate the influence of tooth deflection angles on the rock-cutting efficiency of single-cone bits and obtain the optimal tooth deflection angle as well, rock scraping of wedge-shaped teeth was simulated by a numerical analysis method according to the motion characteristics of single-cone bits and the working performance of the teeth. An optimization methodology for the tooth deflection angles of single-cone bits with wedge-shaped teeth was developed, and rock-cutting tests were carried out on single-cone bits with different tooth deflection angles. The numerical analysis results showed that the working face and scraping volume of the wedge-shaped teeth of the single-cone bits kept changing during scraping rock. The proposed optimization methodology for tooth deflection angles could calculate the scraping volume of the wedge-shaped teeth and obtained the optimal tooth deflection angles accurately and rapidly. The optimizing calculation revealed that the optimal tooth deflection angles were all around 90°. The rock-cutting test results verified the feasibility of the proposed optimization methodology for tooth deflection angles and the accuracy of its calculation results. The research results demonstrated that the proposed optimization methodology for tooth deflection angles of single-cone bit with wedge-shaped teeth can be applied to obtain the optimal tooth deflection angles of the wedge-shaped teeth and direct their distribution on single-cone bits.