The present invention provides a method for updating betweenness centrality of a graph, which obtains the betweenness centrality of an unweighted graph, which is updated when edges are updated. First of all, the method is performed by obtaining a minimum union cycle (an MUC) of the updated graph, and extracting an MUC (MUCU) containing a vertex, which is incident to the updated edge. And a first betweenness centrality due to the shortest paths in the MUCU, and a second betweenness centrality due to the shortest paths, not included in the MUCU, are calculated. And finally, a final betweenness centrality of the graph is obtained by adding the first and second betweenness centralities. By using the method, the search space and calculation cost can be remarkably reduced.