Based on the observation data of temperature and geopotential heights at each mandatory level and the forecast field data of ECMWF during radiosonde type change parallel observation in Yunnan, the observation data of new and old radiosondes are comparatively analyzed and evaluated by using BIAS, standard deviations, Root Mean Square Error (RMSE) and related coefficients. The results show that the observation data of the new and old radiosonde are in good agreement. Below 100 hPa, the temperature absolute observation BIASs of new and old radiosondes are less than 1.0 ℃, and geopotential heights are less than 30 gpm. Above 100 hPa, the maximum absolute BIASs of temperature of new and old radiosondes are 3.9 ℃, and geopotential heights are 151.0 gpm. Except for individual levels in the lower and higher levels, the dispersions of observation data of new and old radiosondes are basically the same, or the dispersion of new radiosonde is relatively small. The new radiosonde observation data is more consistent with the model data and is more obvious at the middle and high levels. Compared with the model data, the BIASs of temperature of the new and old radiosondes are concentrated at about ±0.7 ℃ and ±0.9 ℃, the maximum RMSEs of them are about 3.0 ℃ and 4.5 ℃, and the average related coefficients are about 0.78 and 0.73, respectively. The maximum BIASs of geopotential heights of new and old radiosondes are 28.5 gpm and 130.9 gpm, the maximum RMSEs of them are about 87.6 gpm and 136.9 gpm, and the average related coefficients are about 0.86 and 0.78, respectively.