Abstract:The purpose of the reliability design on civil aircraft environment control system is to ensure the aircraft meet the qualitative and quantitative reliability requirements, reduce the cost in working, and to make better economical and compete ability. In order to ensure the reliability and safety, a fairly large number of technology are used in aircraft environment control system design, redundancy design, mature technology and standardization design. Reliability analysis is used to validate whether mean time between failures and dispatch reliability meet the requirement.