In order to explore the impact of wading engineering construction on the lake system, based on the two-dimensional unsteady hydrodynamic model, numerical simulation of hydrodynamics of the West of Yangcheng Lake was carried out. Based on the correct hydrodynamic simulation, a suspended solids prediction model was established to simulate the transport and diffusion of suspended solids in the West of Yangcheng Lake caused by the water body disturbing from the cofferdam construction of the West of Yangcheng Lake tunnel under different wind directions and construction conditions, and to analyze the impact of cofferdam construction on the water area environment. The simulation results show that the increase of suspended solids concentration caused by water pumping and drainage in cofferdam had the most serious impact on aquatic ecology with the dissipation time reaching 48 h. Under the condition of northeast wind, it was favorable for the dissipation of suspended solids in the south Bay of the West of Yangcheng Lake. The dissipation time during water pumping and drainage and cofferdam demolition were 40 h and 16 h respectively with high concentration area being small. Southeast wind and northwest wind were the most unfavorable conditions. Under the condition of southeast wind, the dissipation time during water pumping and drainage exceeded 48 h and the high concentration area was 0.07 km², while under the condition of northwest wind, the dissipation time during the cofferdam demolition exceeded 28 h and the high concentration area was 0.1 km², which both had great impacts on the water area environment. It was recommended that the water pumping and drainage of cofferdam in the first phase should be constructed in spring and summer, and the cofferdam should be demolished in autumn and winter to reduce the adverse impact on the environment.