The spiral flow in bends can easily causes a problem of river erosion at concave banks and sediment deposition at convex banks in actual bend rivers, and is unfavorable for bank protection engineering. The spur-dikes can effectively control the spiral flow and improve the flow patterns in bends. The time-averaged equations closed with the RNG k-ε turbulence model were used to simulate the flows in bends to analyze the function of spur-dikes in bends. The VOF (Volume of fluid) method was applied to track the flow free surface. The velocity and pressure coupling equations were solved by the SIMPLE algorithm. The predicted water level and velocity distributions in the bend showed a good agreement with experimental data. The spur-dikes can effectively eliminate the problem of river erosion at concave bank and sediment deposition at convex bank in the bend channel, increase the water level in the main channel, and decrease transverse slope of free surface. It can be concluded that the layout of spur dikes is effective in stabilizing the bend flow and preventing bank slope from rushing.