In this paper, the finite element analysis and calculation methods for compensating displacement fatigue and durable vibration fatigue of Pipeline Compensator are research. By comparing and analyzing the calculation results of finite element simulation and traditional engineering calculation method for a certain type of pipeline compensator, the finite element calculation method for compensating displacement fatigue of pipeline compensator is studied, and the finite element calculation process of durable vibration life is explored. The results are compared with test data to verify the calculation accuracy of its design method. The results show that, the accuracy of the finite element method is better than the engineering design method in calculating the displacement fatigue life. And the finite element method can give the definite distribution of the vibration stress and predict the vibration life, which is better than the engineering design method, which can only provide the natural vibration frequency of compensator, vibration stress and life cannot be defined.