Transportation and diffusion of nutrients and pollutants are one of the important procevS-ses in the large shallow Taihu Lake.They influence not only the distributon of water quality, but also the growth of phytoplankton and the algae bloom.Based on the results of a three-dimensional numerical simulation on the dynamicvS in Taihu Lake, China, a three-dimensional model of transportantion and diffusion of conservative substance has been built.The model has been calibrated by the total phosphorus changes from Jan.18 to Feb.22, 1997.The model results in winter are coincided with the observed.It describes that the model can be used to calculate the pollutants and nutrients transportation and diffusion without consideration of biochemical processes in winter in Lake Taihu, China.