Abstract: In this paper, the quality of sounding data for the period from May to September 2017 in Gansu Qingyang region was analyzed and evaluated by comparing with the background of FNL analysis fi elds of NCEP in the United States. The conclusions are drawn as follows: (1) the temperature data of soundings are of high quality and show good consistency. The detailed structure is clear and the error is within ±0.5℃; (2) the humidity data of soundings are of good quality, their consistency is slightly worse than that of the temperature, and the error is basically within ±10%, with wet at night, dry in the afternoon; (3) whether it is temperature data or humidity data, their observed residuals show a trend of increasing fi rst and then decreasing with decreasing pressure; (4) no matter the temperature or humidity, the error is the smallest at the 2 o'clock and the data quality is the best. The quality is comparable at 08 o'clock and 14 o'clock.