Abstract: There are many glutenite formations met when drilling in Mo Liqing area and the characteristics of the lower formation rock are of fine digenetic, compact consolidation, good abrasiveness and weak drillability, and the penetration rate is relatively low. The study of bit type optimum is developed to improve the feed range and drilling speed. First, the well logging data was analyzed and combined together with bit performance data, and the mechanical parameters of the formation such as compression strength, shearing strength, abrasiveness and drillability were collected. Then, the bit database based on the information of the used bits was built. The rational bit type by the matching model between bit type and formation was selected, combining with geology, well logging and drilling data. Then the optimum bit type is chosen and put in use in the field and premium results were obtained.