The observation quality of reflectivity of Shenzhen Qiuyutan X-band phased-array radar is quantitatively evaluated by comparing it to Shenzhen Zhuzilin disdrometer data and Shenzhen Qiuyutan S-band radar data. The results suggest that the reflectivity of X-band phased-array radar is highly consistent with the reflectivity retrieved by disdrometer and observed by S-band radar, with correlation coefficients greater than 0.75 and relative mean biases close to 0, which indicates minimal deviation. The X-band phased-array radar also shows stable performance under different rain intensity periods. However, the deviation of reflectivity of X-band phased-array radar is different under different reflectivity intensities. The reflectivity of X-band phased-array radar is positively biased when reflectivity is under 25 dBz, and negatively biased otherwise. As reflectivity intensifies, the degree of the negative bias gradually increases, and the average bias of reflectivity can reach 8-10 dB when reflectivity exceeds 50 dBz.