Abstract: There are many control gates at the entrances of tributaries to the Changjiang River, which use the process of flood and ebb tide to divert and drain water by themselves.However, the complexity flow pattern makes it difficult to accurately determine the process of diversion and drainage.Taking the Yanglintang estuary in the Taihu Lake Basin as an example, by analyzing the diversion and drainage scheduling methods and flow characteristics, we find that when the middle-hole gate is opened for water diversion during the flood tide, the flow pattern on the inland river side is complex and the water level near it is quite uneven; when all gates are opened for drainage during the ebb tide, the flow pattern on the outer river side is complex and the water level near is also uneven.Therefore, a calculation method for the diversion and drainage flow process of the estuary along the Changjiang River based on compensating for head difference is proposed.In this method, the water level in the weir flow formula was corrected by setting a series of compensated water head difference, and the deviation value between the calculated flow and the measured flow was counted, and then the correlation between the flow deviation value and the compensated water head difference was established.Finally, the appropriate compensated water head difference was determined, so as to establish a calculation formula suitable for the diversion and discharge process of the gates on the Changjiang River tributaries.The results showed that the error of diversion flow calculated by this method was reduced by 40%～50%,and the error of drainage flow was reduced by 3%～6%.Relevant experiences can be used as reference for engineering designers and operation and maintenance personnel of gate management units.