<p>This article concentrates on the reliability of a multi-state supply chain network (MSCN) with supply capacity and transportation emission constraints, in which each route denoting a carrier to offer freight service has multiple transportation capacities due to uncertainties in the transport facilities and vehicles. For an MSCN with multiple suppliers and customers, the commodities supplied by each supplier cannot surpass its supply capacity, and transportation emission should be within a threshold so as to mitigate the adverse impact of transportation activities on the environment. As a result, the MSCN reliability is defined as the probability that the network can transport a sufficient quantity of commodities to fulfill the demands of all customers subject to supply capacity and transportation emission. A minimal paths based method is suggested to compute MSCN reliability, and its utility is demonstrated through a case study. The reliability information can be viewed as decision reference for supply chain management when the environmental effect is considered.</p>