Abstract: In order to study the mechanical properties of shotcrete after reinforcement, the mechanical tests of concrete with different ratios under cyclic loading and unloading were carried out, and the strength characteristics, deformation characteristics and strain changes with time of concrete with different aggregate particle sizes and water-cement ratios were analyzed. The results show that the concrete strength can be evaluated by the ratio of confining pressure when concrete samples are damaged to that when concrete samples are unloaded. The smaller the ratio is, the higher the strength of concrete samples is. In the confining pressure test, the strain of the sample is smaller than that of the conventional triaxial test, the brittle failure of the sample with low water-cement ratio and small particle size is more significant, and the fracture surface is more complete. The failure strength of the sample increases with the decrease of particle size. The sample with high water ash has the characteristics of delayed failure in unloading test.