Aiming at s-band dual polarization weather radar, a improved standard deviation analysis method is designed to evaluation radar data quality. By evaluating the data quality of Chengdu radar base data from February to October 2022, the following results are obtained. Firstly, when calculating the normal radar data, two methods can get the same trend of standard deviation distribution results, and when calculating the error radar data, the results of improved method is better. Secondly,the Zh of Chengdu radar data has great fluctuation, and the proportion of standard deviation lower than the standard value of SDZh is only 43.67%. Lastly, the data quality of Zdr and CC in Chengdu radar is superior. The proportion of standard deviation lower than SDZdr and SDCC standard value is 84.09% and 87.10%. the φdp of Chengdu radar data has great fluctuation, and the proportion of standard deviation lower than the standard value of SDφdp is only 34.54%.