Abstract: In order to improve the efficiency of fatigue analysis for trimmed body, dynamic fatigue analysis methods were investigated. A type of vehicle was chosen as research subject and the finite element model of its trimmed body was built. By performing virtual proving ground (VPG) simulation on multi-body dynamical model of researching vehicle, forces and moments at different interface points were obtained to drive the analysis. Furthermore, analyses based on time domain and frequency domain were conducted. The results of time domain method were set as reference to evaluate the accuracy and efficiency of calculation in frequency domain method. It can be found that the distribution of hot spots obtained in frequency domain method is same as that in time domain method. A criteria for accuracy estimation is proposed that the ratio of damage value in frequency domain method dividing that in time domain method is between 0.5 and 2.0. Among the investigated elements, 78% can meet the criteria. The cost time of frequency domain method was evidently decreased by 82%, when compared with that of time domain method. From our investigation, it can be concluded that the frequency domain method is reliable enough to be applied into fatigue damage analysis of vehicle.