In deep geothermal mining， granite formation encountered in the drilling process will lead to low ROP， high bit consumption， and long drilling time due to its poor drillability， high density and hardness， and strong abrasiveness. In order to improve drilling efficiency， and reduce drilling time and cost， jet-type fluid hammer drilling was used with roller cone bits to efficiently break hard rock formations in geothermal resources survey. At the same time， various drilling process parameters such as displacement， weight on bit， rotation speed， were optimized and field tested for multiple times. Application results showed that for the same footage drilled in hard rock formations， jet-type fluid hammer drilling increased drilling efficiency by 30% over conventional drilling， which greatly increases the mechanical drilling speed in hard rock formations， and effectively increases drilling efficiency， achieving high-efficiency rock breaking. It can provide important technical support for drilling speeding up and increasing drilling efficiency in granite and other hard rock formations.