From the viewpoint of a distributed service process, an ion-channel based method was proposed to analyze the reliability of supply chains. An analytic method was presented to determine the reliability of supply chains for logistics systems. New models were built to consider the following situations: when the nodes failed, different defect states had different measures and effects on the system. A Markov model was introduced to analyze the system safety and aggregate states to get the number of repairs and length of time before the system became dangerous by using ion-channel modeling theory. Finally a numerical example was presented to illustrate the results obtained in this paper.