Abstract: Investigations on the rodent community structure in 3 ecotypic areas of Dongting Lake region in 2001 showed that Apodemus agrarius and Rattus confucianus were the dominant species in the three different ecotypic areas of the region.Apodemus agrarius inhabited mainly in the farmland,immigating from field to field seasonally following changes in crop cultivation and even invaded forests on hills.Rattus confucianus was the dominant species in the forests.The boundary areas between forest and farmland on the hills and mountains were dominated by both of them.Historical statistics in the region showed that Rattus norvegicus had once been the dominant species in the farmfield,but now it dropped rapidly in proportion and was displaced by Apodemus agrarius in dominance.Moreover,the dominance of Rattus norvegicus in farmhouses was also taken over by Mus musculus.