Abstract: In order to understand the influence of arrangement of the longitudinal connection system on the radial gate stability, taking a radial gate of the open-top spillway of a reservoir as the research object, combining the six common arrangement forms of the longitudinal connection system, the static and dynamic analysis on the gate model were carried out by using the finite element software ANSYS. The results show that the arrangement of the longitudinal connection system has a great influence on the gate arm, the A-shape arm is not suitable for the large-span and large-radius open-top arch gate, and the longitudinal connection system has little effect on the natural frequency of the gate. By analyzing the various modes of the gate, vibration is most likely to occur for the supporting arm. This conclusion has certain reference value for the optimization design of radial gate arm.