Abstract: Taking the domestic first S-band business test dual polarization radar (CINRAD/SA-D) produced from Beijing Metstar Company as a study object, a comparison analysis was carried out with WSR-88D dual polarization radar from the aspects, including hardware upgrade, online/offline calibration method, signal processing and software technology. And the long-term calibration with internal signal source method and the results of the whole link calibration with light rain method were analyzed. The results show that the statistical variance of the differential reflectivity factor ZDR and the differential propagation phase DP with signal source method are 0.205 3 dB and 1.135 8°, respectively. The standard deviation of the ZDR can be controlled within 0.5 dB with light rain data selected from the key parameters. These results are comparable to WSR-88D weather radar. This work has a very important significance to guide the domestic dual polarization radar upgrade.