Based on the CINRAD/SA radar observations in Beijing and Tianjin, the radar echo evolution characteristics of two convective cells A and B in a severe convective storm affecting Beijing on June 30, 2021 are analyzed. Through the analysis of the variation of various physical parameters and the number of grid points of different reflectivity intensity grades in different stages of cell development and before and after operation in the statistical area. The evolution characteristics of cells with different strengths under different operating conditions are obtained. The results show that the cell B is a normal convective cloud cluster (life time is 3 hours), and after the large dose operation (74 rockets and 58 anti-aircraft guns are effectively operated within 24 minutes) in the early stage of development, it can be seen that the cell B has good characteristics of inhibiting the development of the cell. The parameters such as mean reflectivity, storm body height and vertically integrated liquid water at different heights of the storm body all show a downward trend. The number of grid points of the stronger echo (30-60dBZ) decreases, while the number of grid points of the weaker echo (20-30dBZ) increases rapidly, and the convection structure weakens as a whole. Cell A is a supercell (life time is 5.5 hours), and there is no obvious inhibition effect in the initial stage due to insufficient operating dose (15 rockets are effectively operated within 30 minutes). Near the mature stage, continuous high-dose operations were carried out (105 rockets and 182 anti-aircraft guns were effectively operated within 80 minutes). Although some characteristics similar to echo B can also be observed: the average reflectivity, cloud top height, strong echo thickness, vertical integrated liquid water and other parameters in the upper layer decrease, the number of grid points in the higher reflectivity intensity range (50-70dBZ) decreases, and the number of grid points in the lower reflectivity intensity range (30-50dBZ range) increases and lasts for about 30 minutes. However, the overall work suppression effect on supercell A is not obvious.