A 2-D non-uniform sediment mat hmatical model in the boundary-fitting orthogonal coordinate system was develop ed in this paper. The governing equations, the numerical scheme, the boundary con ditions, the movable boundary technique and the numerical solutions were present ed. The model was verified by the data of the reach 25km upstream the Jialingjia ng estuary and the 44km long main stream of the Chongqing reach of the Yangtze r iver. The calculated results show that, the water elevation, the velocity distri bution and the river bed deformation are in agreement with the measured data. A 2-D non-uniform sediment mat hmatical model in the boundary-fitting orthogonal coordinate system was developed ed in this paper. The governing equations, the numerical scheme, the boundary con ditions, the movable boundary technique and the numerical solutions were present ed The model was verified by the data of the reach 25km upstream the Jialingjia ng estuary and the 44km long main stream of the Chongqing reach of the Yangtze rver. The calculated results show that, the water elevation, the velocity distri bution and the river bed deformation are in agreement with the measured data