Abstract: The curvature of an artificial open channel bend is mostly a constant that is hardly to be matched by the curvature of flow dynamic axis, thereby causing a separation of fluid and solid and the formation of secondary flow. This study adopts two types of transition curves connecting a circular bend section to plane walls at its inlet and outlet in modification of an artificial 120?-turn open channel bend with abrupt curvature changes, and examines the improvement of its flow and sediment transport condition. For this purpose, the MIKE 3 FM hydrodynamic and sediment transport model is used to simulate the 3-D bend flows, focusing on comparison of near bed velocity, variation in water surface, secondary flow, and bed topography between the bends with and without wall transition curves. Results reveal that the transition curve modification is effective in significantly suppressing the development of turbulences in the bend and reducing concave bank erosion and convex bank sediment deposition.