The invention relates to a complex network key node cluster mining method, and specifically discloses a complex network key node cluster mining method based on combination optimization, which is usedfor solving problems of simplified technical indexes, high cost needed for node mining, limited propagation range, insufficient amount of propagation information and no consideration of a strengthening function of reachable neighbors to node centrality in the existing method. The method provided by the invention has the following steps: 1, building an input network model; 2, selecting indexes forpreprocessing network nodes; 3, calculating an initial key node cluster S<2> and a to-be-optimized node cluster S<3>; 4, selecting an objective function of key node cluster combination optimization; 5, performing combination optimization; 6, outputting a key node cluster S. The method provided by the invention has the advantages of preprocessing network node groups, selecting limited nodes for performing combination optimization, being low-complexity in calculation, considering various indexes, preprocessing the network nodes and performing combination optimization for the obtained nodes, andmining the key node cluster which needs low cost for mining, has wide propagation range and large amount of propagation information, and considers the strengthening function of the reachable neighborsto node attributes.