Abstract: The performance of a one-dimensional (1D) thermal diffusion lake model for Lake Taihu has been examined using obscrvations from August 11 to 28,2010.The originally simulated lake surface temperature has significant biases, and the simulated temperature diurnal cycle range is smaller than observations.Eighteen sensitivity experiments were conducted with the ccological environment and pollution conditions in Lake Taihu included.The results show that three parameters that depend on the lake type should be modified as follows; increase extinction coefficient by a factor of 3,change the fraction of the non-refleeting shortwavc radiation absorbed by the lake surface from 0.4 to 0.8,and parameterize the roughness length via a function of wind and lake depth.The new lake model using the new parameters has greatly improved the temperature simulations when compared with observations and original simulations.The vertical thermal structure in Lake Taihu is well reproduced using the three new parameters in the lake model.The simulated sensible flux and latent heat flux arc also improved significantly.A serics of sensitivity tests were performed to determine the critical meteorological variables (solar radiation,air temperature,and wind)affecting the simulations of water temperature.Thus, a ±10% error has been exerted in these three main meteorological variables, and the result shows that this lake model is not very sensitive to those meteorological variables.By contrast,this lake model is less sensitive to the winds,the sensitivity is almost the same for the other two variables.