Abstract: The failure analysis research of rock drilling hammer heads is of great significance for improving the operational efficiency of rock drilling vessels, ensuring project progress and waterway safety. The microstructure, composition and mechanical properties of failed hammer heads were analyzed by means such as metallographic microscope, chemical testing and mechanical properties tests. The heat treatment process of hammer heads during manufacturing was simulated and calculated with JMatPro thermodynamic software. Then, the failure causes of the rock drilling hammer heads were discussed, and the specific measures for performance improvement were proposed. The results showed that the failure of rock drilling hammer heads was caused by the severe deformation of the base part of hammer heads. It was mainly due to the fact that the contents of Si and Cr in the base alloy of rock drilling hammer heads were lower than the required values specified in standard of GB/T 5680-2010 for ZGMn13Cr2 steel, while the contents of Mn and Mo were at the lower limit of standard requirement, resulting in insufficient strengthening effect of hammer heads. In addition, the water hardening treatment temperature of hammer heads was lower than the conventional water hardening temperature of high manganese steel ranging from 1 050 to 1 100 ℃, which had a limited strengthening effect on the hammer heads, causing the strength of hammer heads to fail to meet the standard requirements. The following measures could enhance the strength and hardness of hammer heads: increasing the content of alloy elements such as Si, Mn, Cr and Mo in hammer heads, and controlling them at the upper limit of standard requirement; raising the water hardening temperature to 1 060 ℃, and taking measures such as increasing the refining process, etc.