For solving the potential flowinduced vibration problem of the tainter gate located at the bottom outlet of the Three Gorges Project,the study on these problems was performed by a perfect hydroelastic model.The hydroelastic similarity criteria,the properties of the newly developed hydroelastic material,the results of mode analysis of the gate and the results of the model test are presented in thepaper.It was found that in the scale model investigation severe selfexcited vibrations take place when the gate is partially submerged by the tailwater level under no side seals(or the side seals being damaged) condition.However,when both side gaps of the gate are blocked from upstream to eliminate the gap jet flow,the gate only suffered weak vibrations.The cause of severe vibration is the formation of a selfexcited vibrating system by the coaction of the gap jet and turbulent flow downstream the gate.When the gap jet is eliminated by seals the severe selfexcited vibration doesn't occur.