Using multi temporal satellite images of remote sensing, wetland information was extracted by decision tree classification method combined with field surveying and four Lake Dongting's wetland type distribution maps were drawn out. This paper mainly analyzes the dynamic characteristics of wetland vegetation, driving factors and their influence on the wetland ecosystem in this region. Results show that vegetation community distribution and proportion changed obviously. In the past 17 a, forest area increased by 367.88 km² at a rate of 1127.51%. The forest area extended to main part of beaches and became the main vegetation type of Lake Dongting. Reed area decreased by 44.09 km², while sedge land area increased by 2.99 km², with change rate of -5.80% and 0.40%, respectively. This change resulted from both natural environment evolution and human activities. The destruction of natural wetland vegetation, especially planted reed and poplar, destroyed the structure and function of Lake Dongting wetland ecosystem. In order to protect the Lake Dongting wetland effectively, we must rationally exploit bottomland resource, protect natural wetland vegetation and make good management on shoal forestation.