Caused by the poor bit adaptability and frequent tripping, low ROP and long drilling cycle of the horizontal well drilling in Honghe oilfield severely restricted the drilling speed and efficiency. A correlation mathematical model of rock drillability and acoustic logging is established based on laboratory drillability experiments on the cores of Honghe oilfield, and the rock drillability grade profile is determined. The experiments and calculated results show that the drillability grade in the Honghe oilfield formation ranges from grade 3～6, the upper part belongs to soft formation and the lower part medium-hard formations. PDC bit is selected based on formation drillability, the average single bit footage and ROP are largely improved and the drilling cycle is shortened in the field tests and application, horizontal well drilling speed and efficiency improvement have been achieved.