Abstract: The feasibility of GPS precipitable water vapor is discussed according to the com-parison of Radiosonde and GPS precipitable water vapor which the correlation coefficient was 0.94 and the RMS was 4.0 mm.Precipitable water vapor change in Chinese mainland in 2004 is figured with the gridding method of splines in tension,according to the GPS data of the crust monitor observation network of China,combined with the relevant meteorology infor-mation.According to the distribution of Chinese annual amount of rainfall,it can be conclu-ded that the total trend of the precipitable water vapor is diminishing from the south-east coastland to the north-west inland.In China,the precipitable water vapor reaches the apex during july and august,and it countermarches the trough during january and february.Ac-cording to the precipitable water vapor,from high to low,all districts can be ranked as south-east coastland,the inland and the tableland.