To study the underwater reef damage characteristics of the high frequency hammer in the sensitive area of the Yangtze River channel,theoretical analysis and numerical simulation are used to analyze the damage characteristics and influence rules of the reef under the impact of the high-frequency hammer.The results show that the rock mass around the impact drill rod is mainly shear damage,while the rock mass away from the drill rod is mainly tensile damage.The penetration depth,crushing depth and crushing width increase with the increase of working pressure and impact frequency,and decrease with the increase of reef strength.The high-frequency crushing hammer should not break the reef with too high strength.When the impact frequency is greater than the critical frequency,the improvement of the crushing parameters is not significant.The working pressure is the main factor affecting the reef breaking effect of the high frequency crushing hammer,followed by the impact frequency,and finally the reef strength.The mathematical relationship between the drilling depth of drill rod and the volume of rock mass is established,and the calculation method of reef breaking efficiency of high-frequency hammer is put forward.The research results have reference value for optimizing reef breaking parameters and improving reef breaking efficiency.