Abstract: In the drilling of DTH hammer with large diameter, the plan arrangement of cylindrical tooth and the choice of tooth type are the decisive factors affecting the drilling efficiency, the service life of drill bit and the quality of hole drilling. At present, developed design ideas have not yet been presented in this field at home and abroad. Based on the Equal Working Condition Tooth Arrangement Theory, through the rock breaking mechanism of cylindrical teeth, the effect of adjacent cylindrical teeth on rock breaking is discussed. Thus, the optimal tooth spacing, the optimal tooth position and reasonable number of teeth are determined. Impact energy is used to determine the number of teeth, and the selection methods are summarized, including cylindrical tooth, alloy materials of cylindrical tooth, etc. Two different designs of φ800 mm DTH hammer bit are proposed for different strata of soft rock and hard rock.