In response to the call of General Secretary Xi's“Yangtze River Protection”，two lakes in Jiujiang（Gantang lake-Nanmen lake）are planned to carry out a series of water environment comprehensive treatment projects including shore interception，water ecological restoration and live water flow engineering，in order to achieve the Class IV water quality target.The mathematical model of hydrodynamic and water quality was established by MIKE 11，MIKE 21 and MIKE FLOOD.The flow field and pollutant concentration field of the two lakes were simulated and analyzed，and the water quality target accessibility of the water treatment project was evaluated.The research shows that after the implementation of the project，the spatial compliance rate of each water quality index of the two lakes is up to 90%，and the water quality compliance rate of sunny days is greater than rainy days；there are about 8.63%of the rainfall period （rainfall more than 31mm/d）exceed the water quality standard，which can re-standard after several days of recovery．