Abstract: Based on the characteristics of the strength stress of bellows, the extraction and calculation of bellows stress including circumferential stress and meridional stress in element coordinate system were discussed. Stress state of half corrugated shell was analyzed and compared with the calculation according to design specification. At last, a new way of checking the strength stress of bellows was put forward in terms of node stress with FEA, such as polynomial fitting employed to check the circumferential stress. From the result of polynomial fitting, the proposed stress check based on finite element could guide practice.