Water vapor plays a very important role in weather and climate changes. Though water vapor is very little in the atmosphere, but its change, in the atmosphere, is very obvious. Water vapor is also an important kind of greenhouse gas in the atmosphere whose spatial distribution is extremely uneven and time variation is very fast. It is not only the main driving force of weather and climate changes, but also an important formation and evolution reason for disastrous weather, especially medium or small scale disastrous weather. In satellite geodesy, GPS positioning accuracy was primarily affected by water vapor. Therefore, people learn from the elimination of noise in the measurement process, gradually to develop out of a new discipline—GPS meteorology (GPS/MET). Along with the development of GPS meteorology, people start to utilize ground-based GPS technology in order to effectively compensate for the defects of traditional detection technologies spatially and temporally and obtain water vapor information with high-precision, high-capacity and high space-time resolution ratio through ground-based GPS water vapor monitoring network. How to measure water vapor content in the atmosphere, to monitor the distribution of water vapor and its trends, which have an important practical significance to meteorological department, especially in monitoring and forecasting disastrous weather on a medium or small scale. The main content of this paper is to launch the development of ground-based GPS water vapor monitoring system; the purpose is to make this system fill in the blank of the application of GPS inversion water vapor technology in Sichuan and even the southwest areas of China, and also enhance the capacities of meteorological department on forecasting and monitoring of medium or small scale disastrous weather, as well as promote the work of many related meteorological operations.