Abstract: According to the principle of water balance, in a given period of time the difference between the water income and the water output in the atmospheric column in a studied region is equal to the variation of the water vapour content in the atmospheric column in that region. Utilizing the data of about 100 stations for 10 years(1961-1970),We calculated and analyzed the water vapour content in the atmosphere of every month and the whole year in China and the variation of water vapour in every month. Combining the precipitation and evaporation we investigated the water budget in the atmosphere in China.