Abstract: Radial gates for the deep orifices of Xiluodu dam are operated by 4 000 kN/ 1 000kN swing hydraulic hoist. To meet the requirements on the gates and hoist manufacturing, installation error, the hoist swing frame was designed as the same level two-way cross style. Four supporting beams of small frame were steel castings, connected by the tenon. It's complicated and difficult to use traditional mechanical method to simplify a suitable calculation model for the loading situation of the tenon parts. The three-dimensional finite element method was adopted here to check and analyse the structural strength for the frame.