Abstract: This paper analyssed the effects of re-submerging particular polders on the ecological environment of Dongting Lake based on summarizing the ecological environment effects of land reclamation.The favorable conclusions of the project such as expending the ability of passing and storing floodwater,improving the local climate and water quality,favoring the biodiversity protection and the sustainable utilization of water resource were obtained.It is indicated that the migratory towns construction will bring risks of water pollution.Proposals and countermeasures of Dongting Lake ecological environment protection were put forward.

Key words: Bactrocera cucurbitae, MtDNA, Cytochrome b gene, Genetic differentiation