In order to compare the difference between Lband and 59701 upperair sounding systems, an analysis is made of the temperature, pressure, and humidity data of Hangzhou for a whole month by mean of the deviation and mean square deviation methods. The results indicate that compared with the 59701 sounding system, the temperature and height data from the Lband sounding system are more stable and less discrete, which is favorable to the improvement of weather forecasting. There exists a distinct inflexion point at 70 hPa in temperature difference between the two sounding systems, and the reason remains to be studied further.