Abstract: In view of the problems affecting the operation safety of the water flow characteristics of the lateral inflow inverted siphon,such as the flow characteristics are affected by the inflow and boundary conditions,the flow conditions of the pool are complex,which is easy to produce suction vortex. We took the Dali inverted siphon project of Dali Section II of the Yunnan-Dianzhong Water Delivery Project as an example. The gravity similarity and similar vortex were considered,and the physical model test method with a geometric scale of 1∶20 was used to study the flow pattern and vortex characteristic parameters of the lateral inlet inverted siphon. Research shows that:by adjusting the shape of the right side wall of the inlet pool,extending the diversion pier,adding integrated vortex board and trapezoidal vertical beam vortex elimination measures,the backflow and vortex of the inlet pool can be effectively eliminated to improve the flow pattern of the inverted siphon inlet and eliminate the suction before the inlet. The proposed vortex elimination measures applicable to the side-injection inverted siphon into the pool can stabilize the lateral flow,destroy the conditions for the vertical shaft vortex,and can better solve the flow pattern of the inverted siphon. The study can be used as a reference for the improvement of the bad flow pattern of lateral inflow.