The accuracy of the aircraft cabin door trajectory is directly related to flight safety. Uncertainties such as manufacturing and assembly errors can easily lead to trajectory deviations and jamming risks. Therefore, this paper proposes a tolerance analysis method for cabin door lifting trajectories based on interval mathematics: the cabin door lifting mechanism of a certain model of passenger aircraft is simplified to a four-bar linkage, and a theoretical model of the stop block trajectory is established; through sensitivity analysis, the linkage rods that have the greatest impact on the trajectory are obtained; then the rod lengths are set as interval variables, and interval operations are introduced to calculate the uncertain range of the trajectory, generating the trajectory variation range; and it is observed whether the trajectory variation interferes with the limit device. The calculation results show that considering the interval variables effectively represents the variation range of the cabin door lifting trajectory caused by rod errors. The variation range of part of the trajectory is significantly larger than the limit device on the aircraft door frame, indicating that due to rod errors, the cabin door will interfere with the limit device during lifting, causing jamming when opening the cabin door. The research proves the feasibility and effectiveness of using interval mathematics for tolerance analysis of cabin door mechanisms, providing a basis for tolerance quantification allocation, precision optimization, and data-driven fault diagnosis in mechanism design.