Experimental hot dry rock development wells are drilled under high-temperature and hard rock formation conditions where there are still many technical difficulties in how to achieve efficient drilling. Air DTH hammer drilling technology is one of the effective methods to solve the problems with drilling in hard rock formations. The DTH hammer bit is the key tool for air drilling. Through the application of air DTH hammer drilling technology in the hot dry rock well GH-01 in Gonghe of Qinghai， the paper analyzes and discusses the problems of broken teeth， severe wear and short service life of the air DTH hammer bits. The air DTH hammer drill bit was optimized from several aspects， such as drill bit structure design， drill bit processing material selection， and drill bit cold pressing and tooth fitting technology. The finite element analysis method was used in the optimization process of tooth fitting to simulate and calculate the interference of the cold-pressing tooth fitting process， and according to the results of analysis and calculation， the optimal interference of tooth fitting was determined. The optimized structure， materials， and processing of the DTH hammer bit can provide some reference for the development of air DTH hammer bits suitable for drilling high-temperature hard rock， improve the comprehensive drilling efficiency of air DTH hammer drilling， and provides technical support and reserve for the development of hot dry rock.