The principles of GPSbased water vapor remote sensing are introduced. The atmospheric integrated water vapor content over Harbin was retrieved by means of the measurements of the Harbin GPS station in June 2004, and the results with the error being 2.7 mm (comparing with the computed water content by radiosonde data) were obtained. The errors and the influence degree on the precipitable water vapor results are analyzed. Comparison is conducted between retrieved and observed, as well as the radiosonde data. The findings conclude that the retrieved results are applicable.