Abstract: Aiming at the research blank of the reliability evaluation of high failure rate Line Replaceable Unit (LRU) and the location of LRU fault component in the aviation maintenance, a reliability evaluation simulation model applicable for LRU "replacement maintenance" strategy is designed, the design principle and the actual methods as well as steps of each function module in the model are introduced in detail. Finally, the model is applied and analyzed to a common high failure rate LRU in a certain type of aircraft hydraulic system as an example, the conclusion shows that the simulation model is practical and universally applicable to the reliability evaluation of LRU.