In order to solve the vibration problem of Sshaped welded metal bellows,the surface was selected to instead of the solid element of wave plate for numerical modeling and modal analysis;the influence of the element size on the vibration frequency of the bellows was studied.It was proposed that the element size needed to less than 0.5 mm when the face unit was selected,and its effectiveness was verified.The vibration test was carried out by using the electric vibration test platform,and the vibration characteristic curve of the bellows was obtained.Through the comparison of the simulation results and experimental test results,the natural frequency and vibration mode of the first 6order vibration of the bellows were determined,the vibration mechanism and influencing factors of the bellows were revealed,and the numerical modeling method and experimental testing technology for the bellows were clarified.The research results provides a reference for the design,manufacture and application of the welded metal bellows.