The invention belongs to the field of drilling machinery, and particularly discloses a mutual-lock hammer valve mechanism for improving the working performance of a hydraulic impactor. The upper of a drainage tube is inserted in the bottom of an upper connecting head, and the lower portion of the drainage tube is inserted in the top of an active valve. The top of the active valve is externally clamped in a limiting pad. A positioning sleeve is arranged between the bottom surface of a boss in the middle of the drainage tube and the limiting pad. The lower portion of the active valve is provided with a hammer-impacting rod. The outer portions of the active valve and the hammer-impacting rod are sleeved with hammer-impacting rod upper section connecting heads. The active valve is slidably matched with an inner hole of the hammer-impacting rod upper section connecting heads. The top of the hammer-impacting rod and the connecting heads of the upper section of the hammer-impacting rod are fixedly connected. The hammer-impacting rod and the hammer-impacting rod upper section connecting heads constitute a hammer-impacting assembly. The lower portion of the hammer-impacting rod is provided with an impacting anvil bed. A lower cylinder sleeve is externally sleeved with the bottom of the hammer-impacting rod. The bottom of the upper connecting head is sleeved with the top of an outer tube. The impacting anvil bed is sleeved with the bottom of the outer tube. According to the mutual-lock hammer valve mechanism, the closing and sealing performance of an impacting hammer and the active valve of the hydraulic impactor is improved, the synchronization coordination and reliability of the combination of the hammer and the valve are ensured, and the water power utilization ratio and working performance of the hydraulic impactor are improved.