Abstract: Taking Poyang Lake wetland as the research object,using the theories and technologies of GIS,RS,GPS,spatial database,three-dimensional virtual simulation and hydrodynamic theories,we constructed the fundamental GIS for Poyang Lake wetland with the integration of expert knowledge,model and decision making functions.To a certain extent,the system solved the contradictions in wetland economic development—different sectors(e.g.pollution and hydrological monitoring,flood forecasting,land planning) are closely related,but isolated from each other.