The effect of submerged guide vanes in the river regulation is systematically analysed.It is considered that the secondary flow caused by submerged guide vanesin the concave bank of meandering reach can eliminate the circulation flow and in straight reach may promote the sedimentation in the guide vanes region,becausethe submerged guide vanes canincrease the flow resistance and abate the bottomvelocities at the vanes area.The results of systematic analyses are in agreement with the data of experiments and engineering practice.