Abstract: Reliability theory was introduced into the protected layer mining，by summarizing seven main influencing factors. Besides the corresponding evaluation index，target layer，criterion layer and sub-criterion layer of the reliability evaluation system were also established. Based on the basic theory of analytic hierarchy process (AHP)，the judgment matrix was built to calculate the importance weight of the index method. According to its importance degree，the influence of every index on the system reliability was divided into four levels. Finally，the field case was analyzed in view of the reliability evaluation，which could provide a reference for other project cases.

Key words: protected layer mining, AHP, reliability