Traditionally, it is absolutely difficult to collect SSC data(suspended sediment concentration) in the whole lake and impossible to decide the time derivation of SSC with small time interval either. Based on acoustic backscatter theory, this paper presents the denary logarithmic relationship between SSC and the emended ADP signal strength in Lake Taihu on condition that the components of suspended sediment do not change dramatically. Verification is also conducted based on the observation made at Wugui island in July 2002. The satisfactory results suggest the method is available in Lake Taihu and has bright prospect in determining SSC.