Understanding the spatial differences of ecological functions of the coastal wetlands in the Yancheng is of great importance for wetlands protection and exploitation. Hydrogeomorphic unit (HGMU) is a base condition for ecological function assessment. Based on the distribution of wetland types abstracted from Alos imagery in 2006-2007 and field surveying on hydrological condition and DEM(1∶25000), the hydrogeomorphic units were determinated for evaluation of wetland ecological functions in the study area. The results showed that the coastal wetlands of yancheng can be classified 7 HGMUs. Each HGMU has similar ecological functions, and different HGMU has clear different ecological functions. Among these HGMUs, the double direction of freshwater\|flooding area(estuary area), daily tide\|mud and sand flat area and monthly tide\|mudflat, as well as annual tide\|grass flat area had better ecological functions than other areas in the coastal wetlands of Yancheng. Therefore, to conservation these HGMU wetlands are of significant importance for maintaining regional ecological functions in the coastal area.