Plants of different growth forms have different plant traits, while plant traits determine their adaptive capacity to the environment. Dianshan Lake is a typical eutrophic lake in China. In order to find out the key driver in the succession of submerged vegetation and the future direction of succession, the research investigated the present state of submerged vegetation in Dianshan Lake, measured plant traits, analyzed the adaptive capacity and response mechanism .The results indicated that: submerged vegetation of different growth forms adopted different strategies, which determine their distribution. Magnopotamids plants Potamogeton malaianus could establish communities in large area of waters, because of its high tissue intensity. Parvopotamids plantsHydrilla verticillata, whose characteristics are small leaf, high specific leaf area, high specific leaf area divided by shoot dry weight and locating most leaves in upper water layer, were capable to exclude other species and form density communities in small area of waters. The disappearance of communities of Vallisnerids plants Vallisneria natans was mostly due to the traits of large leaf and locating most leaves at the bottom of water. Species capable to survive in eutrophic waters all had the traits of small leaf and locating most leaves in upper water layer, which helps to get the light in upper water layer. These results indicated that the available light underwater was the key factor to drive submerged vegetation succession.