Using the data of Guangzhou S-band dual-polarization radar and X-band phased array radar, we analyze the radar observation characteristics of a supercell on March 26, 2022. The results show that this supercell showed classical structural features such as hook echo, drape echo, and three-body scatter signature (TBSS). Other structures, such as low-level convergence, upper-level divergence, mesocyclone and anticyclones, contributed to the maintenance of the supercell. Analysis of the polarization features shows that the differential reflectivity (Z_DR) arc appeared in the low layer of the supercell, and the high reflectivity corresponded to low Z_DR, low correlation coefficient (C_C) and high specific differential phase (K_DP), which conformed to the characteristics of melting hail. The polarization characteristics of the Z_DR ring, C_C ring and TBSS were observed in the middle layer. The high-rise strong-echo regions corresponded to low Z_DR, higher C_C, and low K_DP, helping to identify large hail. The Z_DR and the K_DP columns were observed in the vertical direction, and the maximum development height of the Z_DR column reached 8 km. The K_DP column could reflect changes in the region of the supercell containing large amounts of liquid water droplets, and the K_DP foot could identify the region where the heavy precipitation was located. The faster scanning speed of X-band phased array radar could finely monitor the formation and evolution of supercell hook echo and mesocyclones. Z_DR arc and melting hail features were also observed at low layers with patterns similar to those by S-band dual-polarization radar, but the effects of attenuation should be dealt with with caution.