Short-term adverse weather conditions have a direct impact on geological disasters. However, the data source of high-precision weather on real time can be provided by GPS technology. At the same time, the high-precision and real-time weather forecast can provide important and basic information for geological disasters monitoring, forecasting and prevention. However, the precision of the total zenith delay in troposphere directly affects the estimating precision of the water vapor contents over stations, which affects the accuracy of real-time weather forecast. In this paper, the total zenith delay of GPS observational station is solved respectively by GPS data on GPS observational station grouped with different IGS stations using high-precision software-GAMIT/GLOBK developed by the Massachusetts Institute of Technology. The solving results are comparatively analyzed to draw：the best number of IGS tracking stations by grouping network for improving the precision of the total zenith delay in troposphere is 3. It is of great realizable significance.