Plants of different growth form have different plant traits, which determine their adaptive capacity to the environment. Dianshan Lake is a typical eutrophic lake in China. The research investigated the present state of submerged vegetation in Dianshan Lake, assayed their plant traits, analysis the adaptive capacity of submerged vegetation of different growth form, in order to find out the key driver in the succession of submerged vegetation and The future direction of succession. The results indicated that: submerged vegetation of different growth form have different plant traits, which determine their distribution. Magnopotamids plants Potamogeton malaianus could establish communities in large water, for its high tissue intensity. Parvopotamids plants Hydrilla verticillata, which were characteristic of small leaf, high SLA and SLA for shoot combined with locating most leaf in higher water layer, were capable to exclude other species and form density plant beds in small water. The decline and vanishing of communities of Vallisnerids plants Vallisneria natans was most due to the traits of large leaf and locating most leafs at the bottom of water; species capable to survive in eutrophic waters all had the traits of small leaves (high turnover rate to grow fast to break the light limits in the bottom water) and locating most leaves in higher water layer (for photosynthetic tissue to get most light). These results suggested the mount of light availability was the key to drive submerged vegetation succession.