According to the in situ measured data on 32 sampling sites in Lake Chaohu in June 2009, the spectral characteristics of diffuse attenuation coefficient (K_d), dominant factors, spatial distribution, as well as the relationship between K_d and K_d (490) in 400-700nm bands were analyzed.On the basis of these analysis, remote sensing inversion model was developed to calculate K_d (490).The results indicate that presented the consistent spectral characteristics.The K_d in 400-600nm showed a exponential decay trend, but K_d from 600nm to 700nm didn't correlate with wavelength.Due to the higher concentration of phytoplankton in some locations, peak values of K_d appeared at 675nm;but K_d showed a feature that was similar to that of pure water in 700-900nm.The dominant factor of diffuse attenuation coefficient was inorganic particles in Lake Chaohu, organic particles took the second place, and CDOM held a minimal impact.In general, K_d(490) in the eastern part of the Lake Chaohu was higher than that in the western part.In the central part, the contour lines of K_d(490) were denser than those in other parts of the lake.K_d(490) was inversed by multivariate linear regression model established with R_rs(591), R_rs(702) and R_rs(842).And the average relative error between measured and in versed K_d (490) was 7.85%.At the same time, the relationship between K_d(λ, λ≠ 490nm) and K_d(490) could be parameterized with wavelength by linear formula in 400-550nm.From 550nm to 700nm K_d(λ, λ≠490nm) was obtained from multiplying K_d(490) by a constant.The relative error between the observed K_d and the K_d(λ), which was calculated by K_d(490) by inversing of the R_rs, was 6.14%.