To improve the inquiring efficiency of regional weather station rain data, a program is compiled with the TSQL clause under VB. The rain data can be obtained with the program from the central database of regional weather stations at the given periods as a background task. The redundancy can be removed from the original database, and the volume of the database is reduced greatly through creating a middle database of hour, day, and month tables. When the longterm accumulation rainfall is inquired, the inquiry is divided into 5 parts, with each part running separately, so the inquiring efficiency is improved greatly. The system can well satisfy the needs of floodcontrol and droughtrelief departments.