By means of the radiosonde data and the threeyear data of the microwave radiometer in Beijing in recent 3 years, from the aspects of total average, daily change, annual mean change, and different sky status, etc, the evaluation and analysis of the retrieval products are made The results indicate: (1) The rootmeansquare error of temperature increased from surface to 5000 meters and decreased above 5000 meters gradually The overall average relative error was less than 02 ℃ with a positive value, which shows that the retrieved temperature was higher than that from the radiosondes (2) The rootmeansquare error of humidity increased from surface to 3000 meters and decreased above 3000 meters, and the overall average relative error was positive, which shows that the retrieved humidity was also higher than that from the radiosondes (3) The error at 20:00 was smaller than that at 08:00 (4) The temperature error was relatively small while it was clear and clear to cloudy, and bigger while overcast or cloudy to overcast The humidity error in overcast and cloudy to overcast weather was small (5) There was a small annual change range in the rootmeansquare error of temperature under 1500 m, but big above 1500 m, smallest in August, biggest in March and April; the rootmeansquare error of relative humidity had a similar change pattern as above under 1500 m, and changed more obviously above 1500 m