Abstract: The Precipitable Water Vapor (PWV) derived from Global Navigation Satellite System (GNSS) can be used for the study of precipitation forecasting, but it needs the support of ground measured meteorological data. In order to solve this problem, a method of precipitation forecasting without using the ground measured meteorological data is proposed and realized in this paper based on the characteristics of Zenith Tropospheric Delay (ZTD) affected by atmosphere. It is validated using the data from Continuously Operating Reference Station (CORS) of Zhejiang province and hourly precipitation during the period from May to June, 2015. The he results show that the proposed method is capable of forecasting 80% of rainfalls, which is equal to the results obtained based on PWV with meteorological data. This indicates that the short-term forecasting method based on the ZTD without considering the measured meteorological data is effective and feasible, which shows significant research and application value for short-term precipitation forecasting.