It was found that bionic coupling bits have higher drilling efficiency than ordinary drill bits by study. On the one hand, bionic coupling bits with higher pressure on the bottom lip surface; on the other hand, it improves the cooling condition. So it has a good prospect in drilling engineering. In this paper, the numerical simulation software ansys was used to analyze the impact of the convex and non-smooth surface on the performance of diamond bit. Comparison was made on the process of drill bits sliding friction on the rock surface with certain pressure under 4 different non-smoothness conditions. Analysis was made mainly on the variation of rock’s equivalent stress, contact friction stress and contact pressure on the bottom lip surface of bit. The convex and non-smooth surface can increase the service life and drilling efficiency of drill bit.