Centralization of complex networks, which can help us find important nodes in complex networks, is of great practical value in many applications. Certification requirements of centrality index are introduced. Degree centrality, eccentricity centrality, closeness centrality, subgraph centrality and information centrality are discussed and their applicability is demonstrated on a certain military communication network. The simulation results show that the center node of network is different in different measures; it reflects differences in the emphasis of various centrality measures. Analysis shows that single measure can't reflect important nodes of networks exactly. As a result, several measures should be considered for the centralization analysis of complex networks based on specific application background.