Abstract: During the excavation of water-rich bedrock by artificial freezing method,the bonding surface between artificial underground ice and rock mass is often affected by dynamic impact,and its stability determines the safety of underground engineering construction. In order to study the dynamic mechanical properties of ice-rock composite structure,the loading system of SHPB was constructed by PFC-FLAC coupling method. The dynamic characteristics and failure characteristics of ice-rock composite were analyzed,and the evolution law of microcracks was studied. The results show that the dynamic elastic modulus of the composite specimen is less affected by the inclination angle θ of the ice-rock interface. Under the action of dynamic load, the crack in the rock of the composite specimen gradually expands from the incident end to the ice-rock interface,and finally forms a penetrating main crack parallel to the loading direction. The propagation of micro-cracks 'guides' the damage process of the composite. The final failure mode of the composite specimen is tensile and shear composite failure,and the failure characteristics of the rock part are mainly affected by the dip angle of the interface. When the dip angle of the ice-rock interface θ is 0°~45°,the peak stress has little difference,while the peak stress increases with the increase of θ,in the value ranges from 45° to 90°