Based on the importance of water vapor in the atmosphere and the advantage of GPS in measuring atmospheric water vapor, several departments, including meteorological departments, institute of surveying and mapping, and astronomical observatory in East China, have established the GPS/MET network. Data is collected to analyze the accuracy of precipitable water vapor (PWV), zenith wet delay (ZWD) and zenith total delay (ZTD), which are derived by GPS/MET. It is compared with radiosonde data within 10 km from GPS stations. The result shows that: (1) The PWV data obtained by inversion of GPS/MET have high consistency with radionsonde result, the average error is less than 1 mm and the relative error is 11.54%. Moreover, the accuracy of GPS/ZTD is even higher and the relative error is less than 1%. (2)The correlation coefficients between inversion of each quantity and radionsonde result are high. Specifically, the coefficients of PWV and ZWD are more than 0.98, while the coefficient of ZTD is 0.977. Apart from that in summer, the coefficient of GPS/PWV is 0.927, and it is more than 0.96 in other seasons. (3)Based on the results of radiosonde data, the accuracy of GPS/PWV is better than results derived by NECP data. It has a broad application prospect in improving the severe weather monitoring, and prediction ability and the numerical weather forecast accuracy.