Based on depth-averaged mathematic model of flow and pollutant transportation in non-orthogonal curvilinear coordinates, the k-ε double equations´ turbulence model and the coupling arithmetic of velocity-water depth are adopted, which are applied to the numerical simulation of the flow and the contamination diffusion-transportation. The flow field and concentration of discharge both along bank and in the centerline of the meandering channel in laboratory are calculated, and the calculating results accord well with the measured data.