In November 2008, April and June 2009, field experiments were conducted with 56 and 31 water samples in Taihu Lake and 30 samples in Chaohu Lake. Then the relation between scattering coefficient and total suspened matter concentrations is analyzed. The scattering model for different seasons and different lakes is developed, and the stable specific scattering coefficient of different seasons and lakes is obtained. Stable scattering coefficient spectral model for different lakes and different seasons is established. Then bio-optical model is used to estimate backscattering ratio, then its spectral dependence is discussed. It can be concluded 1) scattering coefficient of Taihu Lake in different seasons and in Chaohu Lake has stable linear relation with total suspened matter concentrations; 2) Taihu Lake in different seasons and Chaohu Lake have a stable specific scattering coefficient, which is about 0.63 m2/g; 3) Scattering coefficient of Taihu Lake and Chaohu Lake has relatively stable spectral model; 4) Backscattering ratio of Taihu Lake in different seasons and Chaohu Lake is independent on spectrum.