Abstract: To improve economy, compared to the third generation nuclear reactor, the fourth generation nuclear reactor has higher design and operating temperature. Heat exchange tube is an important component of reactor heat exchanger, and finned tube is a kind of heat exchange tube which increases the heat transfer area by adding fins, so as to improve the heat exchange efficiency. The finned tube needs to consider the risk of creep buckling failure because which is at high temperature and under external pressure. This paper focus on the creep buckling analysis and assessment method of finned tube at high temperature. Firstly, the creep buckling analysis and assessment method of the code was used to calculate the critical buckling pressures at different durations. However, this method is only applicable to stainless steel materials whose high temperature duration does not exceed 10 000 hours and the temperature is lower than 700 ℃. Secondly, the finite element method was adopted. ANSYS was used to solve the critical creep buckling time of external pressure cylindrical shell with constant pressure and constant temperature, and a comparative analysis was made based on the analysis results of code method. It provides method preparation for creep buckling analysis of complex structures and load conditions. The eigenvalue buckling analysis was used to get the shape with initial defect. After the initial defect of the structure was obtained by eigenvalue buckling analysis, the initial defect was corrected by multiplying a proportional coefficient to match the maximum tolerance, and then it was introduced into the structure. At the same time, the plastic constitutive and creep constitutive of the material were considered for nonlinear buckling analysis. Then the critical buckling time under different conditions was calculated by numerical fitting, the failure assessment diagram was obtained. Finally, since the external pressure on the finned tube is not always constant, the pressure will change with time. In engineering, the constant maximum pressure for creep buckling analysis was usually adopted, but this treatment is too conservative. In the case that it does not meet the assessment criterion, the actual pressure transient should be applied to calculate the critical buckling time in order to reduce conservation. The critical buckling time under three different pressure transients was calculated to study whether the critical buckling time is related to the load history in this paper. In conclusion, a set of creep buckling analysis and assessment methods for finned tube at high temperature bases on FEM is proposed, which solves the problems of creep buckling analysis and assessment that are not within the applicable scope of code method, and provides method preparation for creep buckling analysis for complex structures and complex loading conditions.