At present, the safety analysis of aircraft air conditioning system is based on the fixed fault state, without considering the dynamic development and change of the fault. At the same time, only qualitative analysis can be carried out. It is necessary to carry out accurate safety analysis on aircraft air conditioning system. Based on the root fault parameters in the FMEA of the air conditioning system, Markov time series is used to solve the lateral fault transfer path, and the joint probability distribution and Bayes algorithm are used to solve the fault level and probability, thus realizing the lateral qualitative and quantitative safety analysis; The Monte Carlo simulation is used to solve the longitudinal upgrading path, fault level and probability of the fault, and the longitudinal qualitative and quantitative security analysis is realized. The results show that the dynamic quantitative and qualitative safety analysis can accurately determine the safety of the aircraft air conditioning system, the release conclusion and the release requirements under fault conditions, and has good engineering application value.