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Morphological changes in rivers lead to serious damages, including changes in the width of the waterways, changes in the drainage plan, erosion and sedimentation of the bed and banks, structural failure and loss of valuable land. A two-dimensional numerical model called CCHE2D was used to simulate the effect of the flow pattern on the river bed changes in the reach of the natural floodplain of the Kor River between the Abbas Abad Bridge and the Dorudzan Bridge, the Province of Fars. The topographical maps of the study area, the geometry of the model, and the computational grid with different dimensions were prepared. Based on the measured flow parameters, a two-dimensional hydrodynamic model of the mean depth, performance and results such as the changes in depth, flow velocity, secondary flow and shear stress were extracted. Finally, two data sets of the RMSE and MAPE were compared using the numerical model simulation versus the collected data. The results showed that this model had a good accuracy in predicting the flow parameter values, ​​and the simulated data were similar to those obtained from field measurements. The results of changes in the flow pattern as an effective indicator in predicting the hydraulic behavior and hydrodynamics showed that by correcting the path and removing the bends in the clay meadows of the Kor River by straightening the meanders, the heavy erosion of meander most agricultural land will be prevented. It must be emphasized that straightening the waterway entails its lining with erosion-resisting materials. It can be seen that using the computational fluid dynamics for modeling the stream bed variations brings researchers closer to a more general predictions for governing the processes in riverine plains. Also, the CCHE2D model has a good ability to predict changes in meandering rivers.