Abstract: This paper,using probability theory,proposed a method to evaluate the reliability of DC method based on Bayesian by studying the results of DC detection.In order to properly consider all kinds of information in processing,using the mixed Beta distribution,the prior distribution parameters and inheriting factor were identified in terms of historical samples,then used the posterior distribution to determine reliability of DC method and decision-making.Finally,combined No.5 Coal Mine of PingMei,calculated the reliability of different mining areas.The results show that this method can be used to prevent and control of water disasters by coal mining enterprises,which could improve the benefit of investment.