At present， China depends highly on fossil fuels in the perspective of the energy structure. In the context of global energy transformation， as a new type of clean energy， hot dry rock has the advantages of huge reserves， rich resources and wide distribution. In view of the technical difficulties in drilling of high temperature hard rock in hot dry energy exploration and development， YZX178 hydraulic DTH hammer was optimized in terms of its structure and applied in hot dry rock wells. The results show that YZX178 hammer is feasible and efficient for drilling hard formation such as hot dry rock. It has the advantages of energy saving， environmental protection， high safety， convenient maintenance， cost saving and high temperature adaptability. However， more work needs to be done to solve the problem of matching the working life of the hammer and the roller bit.