Abstract:A dynamical optimization analysis of a metal bellows for aviation pipelines is carried out with the finite element method (FEM). To avoid the first four order resonance frequencies, the bellows is optimized by maximizing the fi rst order natural frequency as optimization object and taking the wall-thickness , convolution height of the bellows and the position of sustainment as design variables. Based on the results from dynamical optimization analysis , the Monte-Carlo method is introduced to analysis the parameter sensitivity to the natural frequency of bellows system. It is shown that the Young’s modulus, the density of the material property and wall-thickness, convolution height of bellows are major factors to low order natural frequency. Finally, the distributing of the fi rst four order natural frequencies is analysed and the interference theory is used to process the bellows system’s anti-resonance reliability analysis. The results can do help in anti-resonance design and the reliability estimation of bellows system.