Abstract: In this paper,based on the analytical solution of linear diffusion waveequation with water level,a flood routing model of channel is developed,which has clear physical significance and takes all kinds of effects (backwater and lateral inflow) in the flood wave movement into account,so that it has wide useable range.It doesn't require detailed data of cross sections or river bed geometry but requires only their average values.In this model an excellent means to analyze individual or overall effects of boundary conditions is provided.When it is applied to Jingjiang channel of the Yangte River which is a complex network with join of tributaries and distributaries as well as Dongting lake water system,it shows good results.