As the structural support of the low-pressure simulation equipment,the training cabin body is mainly damaged due to the differential pressure load of the cabin body wall,which aggravates the fatigue damage of the stress concentration parts,resulting in partial failure of the structure.Aiming at the fatigue damage problem of the large-scale negative pressure cabin structure,a certain type of low-pressure cabin from a company was used as the prototype,a geometric model including internal stiffeners and transition cabins was created.The static and dynamic analysis was carried out to ensure the rationality of the structural design.At the same time,the three-point rain flow method was used to count and obtain the corresponding cyclic load spectrum;the Goodman equation was selected to correct the average stress and improve the prediction accuracy.Finally,the fatigue life prediction analysis of the structure was carried out by the S-N curve of the cabin material and the Corten-Dolan rule,and the cycle times,fatigue damage and rain flow rectangular diagrams of the dangerous unit parts under the corresponding cyclic load were obtained.The simulation analysis results show that the value of severe fatigue damage is 1.018×10-5,the local circulation number is 9.822×104 times,and the estimated service life is about 15 years.According to the rain flow rectangular diagrams,the average stress is mainly concentrated between 202.1~281.7 MPa,the maximum stress amplitude is 211.8 MPa,and the average stress is mainly tensile stress.