An algorithm is presented to evaluate terminal pair reliability for complex systems. he approach is an extension of the minimal path set concept for non-target nodes, and uses the concept of disjoint branch sets. By means of disjoint branch set techniques, the partial disjoint features of subpaths (i.e., part of a path is disjoint to the rest of the path) are used to reduce the number of path intersections in the calculation of the system reliability.