A simulation method for airborne missile’s lifetime prediction was proposed, in order to deal with the problem of lack of lifetime data in missile system level. Lifetime distribution of key components was analyzed, which includes exponential distribution, Weibull distribution, normal distribution and log-normal distribution. Lifetime sampling equations of those distributions were listed. According to missile’s structure, key components were categorized into 4 types corresponding with storage reliability serial model, parallel model and by-pass model. Lifetime data in system level was generated by key components’ sampled lifetime according to the system storage reliability structure. Then the generated system lifetime data was used to optimize lifetime distribution and calculate lifetime indicates. The predict result show that the method and the predicted storage lifetime well fitted the real statistic data, the predicated results is highly reliable, and the method is useful.