Abstract: In order to alleviate the barrier effect of hydropower project construction on fish migration，efficient and safe fish passage facilities are important engineering measures to restore fish migration channels.In particular，the construction of fish passage facilities for high-head hydropower projects is the technical difficulty of current ecological protection.Firstly，through model test and numerical simulation，the flow conditions under the dam of Wudongde Hydropower Station were studied.Combined with the prediction on fish migration route and its distribution under the dam，a new type of mobile tail water fish tank was proposed，which utilizes the fish trapping effect of the tail water from power stations to collect fish.The test results showed that the fish collection work can be carried out according to the operation of the power station to achieve 〖XC英单引号.TIF，JZ〗multi-point，full depth and large flow〖XC英单引号.TIF，JZ〗 fish collection.As an auxiliary fish collection facility，the new scheme can improve the fish collection efficiency.The research results can provide technical reference for the construction of fish passage facilities in new high dam hubs and existing projects.