The purpose of this study is to develop a dynamic DSS (Decision Support System) interfaced with GIS (Geographic Information System) and agriculture information network, In this study, DSS was developed to assist services which required tremendous and real time data in national scale. The data transmitte'd from the local area by the agriculture network were stored in DBMS (Data Base Management System) and analyzed by GIS. GIS and database tools used in this study were ARC/INFO 7.1.1 and INFORMIX 4.0. ACSAS (Agriculture Calamity Service Asist System) by the system prototype was constructed to solve the problem about the drought counterplan service which was to take the responsibility in the Ministry of Agriculture. It was easy to transfer, process, and analyze the information using the system. Specially, the meteological, the reservoir storage rate and the drought counterplan information were spatially analyzed by the functions of GIS.