Using the PMFT method developed by Environment Canada and the metadata collected by National Meteorological Information Centre of China Meteorological Administration, the inhomogeneity test and corrections are carried out to the monthly geopotential height data of 123 radiosonde stations in China. The result shows that shifts of instruments, update of sounding systems and change of radiation correction method are the main causes for the inhomogeneity in the regional sounding geopotential height data in China. With the height increasing, both the number of the inhomogeneous stations in two observation time and the mean magnitude of correction increase significantly. The correction values are negative at all mandatory levels, which indicates the radiosonde geopotential height data in China is higher systematically. The raw monthly mean geopotential height series of the 123 radiosonde stations in the tropopause and the higher levels of troposphere present decreasing trends, after correction, the trends change to increasing trends. In the middle and lower levels of the troposphere, the increasing trend of the geopotential height becomes more obvious after the correction.