Abstract: The problem of reliability evaluation for complex device networks was studies through model that is designed in terms of structure functions. Comparing with traditional algorithms, it can reduce the complexity to compute such problems and improve the accuracy and operability in the process of evaluation. An instance for computation is given showing the feasibility and effectiveness of the algorithm. It requires neither taking all the cut set and spanning trees as preconditions nor computing the disjoint sum once more, but requires just starting from a spanning tree to determine the network reliability. A algorithm for the reliability analysis of multi-state and all terminal complex device networks is therefore given on the basis of the characteristics of spanning tree and loop-sum theory of network diagram.