Abstract: The compression tests of concrete under different lateral pressures and different loading rates are carried out by using a dynamic and static triaxial testing machine. Based on the improved Najar energy method, a new calculation method for damage variables is proposed to analyze the influences of the lateral pressures and loading rates on the damage evolution of concrete under biaxial compression stress. The analysis results show that:(1) The peak stress increases with the increase of the loading rates. Under the same loading rates, the peak stress increases with the increase of the lateral pressures. When the concrete reaches the peak stress, the decreasing trend of the bearing capacity is not affected by lateral pressures. (2) The damage evolution of concrete under biaxial compressive stress state can be divided into three stages: the elastic stage, the damage acceleration stage and the damage convergence stage. (3) The higher the loading rate is, the faster the damage variable increases in the accelerated development stage and the smaller the strain range in this stage. (4) The lateral pressure has a significant influence on the damage evolution of concrete. The development of concrete damage lags with the increase of the lateral stresses.