Abstract: Abstract: In order to reduce the losses caused by cotton pests and diseases, the prevention and control of cotton pests and diseases has become an important link in the process of cotton planting. Therefore, a timely and effective collection of information about cotton pests and diseases naturally becomes the premise and basis of monitoring and further forecasting. However, traditional way of collecting data by filling in paper manually presents several defects, such as the error caused in space and time, the cumbersome statistics and its time-consuming characteristic. Moreover，temporal resolution and spatial resolution of remote sensing monitoring can hardly reach the standard of monitoring, and the inversion model usually fails in achieving the ideal monitoring effect in terms of different cotton varieties and different growth stages. In comparison, information collection based on Mobile GIS has such advantages as its portability, public participation, instantaneity and accuracy in space and time. Focusing on the process of data collection, transmission, storage, analysis and service provision of cotton pests and diseases, this paper proposes a business solution of cotton pests and diseases information service based on Mobile GIS. The method tries to combine GPS positioning with off-line map loading in the mobile terminals to help acquire the precise location data. Users can mark the location where cotton pests and diseases occur by plotting points or polygon graphics on the map, the deviation of which is within 15 meters. Through the development of Android/IOS mobile terminal, collection time and grade of cotton pests and diseases are offered, which thus help gather the attribute information. By defining JSON data collection module, the unity of different platforms' data collection is achieved. And through network, the data are further sent to the spatial-temporal database in the service terminal. Since the database of this system is Oracle Spatial database, when the server side receives data, the system automatically writes them to the database by using JDBC technology through Oracle API (application programming interface). Then the integrating and storing of spatial data and attribute data are realized. The whole process can be finished in 5 seconds. By using spatial interpolation based on inverse distance weighted method, the information of cotton pests and diseases is visualized, with the accuracy of 70%. Meanwhile, monitoring and forecasting services are provided to the mobile terminal through the server side by using ArcGIS Server. Users can browse thematic map of cotton pests and diseases released by administrator timely, which simplifies the process of information transmission. Through application and practice, it shows that this system has characteristics of instantaneity, accurate positioning, and public participation. The fact that users play the roles of both data collectors and service receivers propels the forming of new mode of geographical information service. In addition, the system also provides effective reference for information collection and agricultural condition monitoring.