Abstract: The traditional Dijkstra algorithm is the classical algorithm to calculate the single-source shortest path for a network diagram,but not suited for two regional-cross network diagrams in reality．In this paper,the new concept of regional signature was put forward,and the regional signature and access-control logic for two regional-cross network diagram were designed too.Based on these,the Dijkstra algorithm was improved．The experiment proved that the improved Dijkstra algorithm can correctly calculate the single-source shortest path for two region-cross network diagrams,its place complexity & time complexity are the same as the traditional algorithm．Through this improvement,the adaptation range of the Dijkstra algorithm was expanded.

Key words: Dijkstra algorithm,Two regional-cross network diagram,Regional signature,Access-control logic