Abstract: This paper presents a "double" subgraph isomorphism method for matching LSI chip images, by which the corresponding relation between isomorphic matched nodes is searched from the region adjacency graph of the segmented chip images. In order to perform the algorithm of isomorphism matching, heuristic information is extracted to improve the searching efficiency. The algorithm uses special criteria of region similarity measure and matching figure of surrounding string to select the starting node of isomorphism matching. In the paper, we present not only the priciple of "double "subgraph isomorphism matching but also the matching result. This algorithm has been employed in practice.