Abstract: With the increase of mining depth, the rock mechanics parameters change and the support mode should be adjusted in time. For infrastructure mines, it is important to accurately obtain the dynamic mechanical properties of rock. In this paper, the main surrounding rock andesite in Jama Copper Mine is taken as the research object,and the conventional uniaxial split Hopkinson pressure bar(SHPB) tests under different loading speeds are carried out, and the dynamic mechanical parameters and failure characteristics of andesite are obtained. Based on the theory of fracture mechanics, the average fragmentation prediction model considering strain rate is developed, and the fragments after impact crushing are scanned by scanning electron microscope. The results show that the dynamic compressive stress-strain curve of andesite can be divided into four stages, and the compaction stage is not obvious when compared to the static curve. The dynamic peak strength and dynamic strength factor increase linearly with the increase of strain rate. The energy absorption density per unit volume and mass crushing energy consumption increase quadratically with the increase of strain rate, and the energy absorption density is linearly positively correlated with the increase of new specific surface area. A dynamic fragmentation prediction model considering strain rate is established, and the theoretical prediction is in a good agreement with the experiment. The andesite specimens under different impact velocities are mainly intergranular failure, and the fracture morphology is fairly complex. Under the same magnification, the mesoscopic fractal dimension D_e is linearly positively correlated with the increase of impact load. This research can provide a certain reference for the optimization of blasting parameters and engineering application of the bottom structure of the natural caving method.