How to find the key nodes in the military Command Control (C²) networks and destroy it are critical to paralyze the enemy C² networks in battlefield. In this paper, the topological model military C² network is modeled by means of complex networks theory under the base of analyzing the connection feature and the function of the node in C² network; then the characteristics of the C² networks are presented, such as the information transmission amount, transmission efficiency, and the information control capability. Finally, an evaluating algorithm of node importance for the C² network is proposed based on the C² relation, function of the nodes and the properties of the network. The simulation result shows that the method of node importance proposed in this paper is effective and the calculating time can be decreased with the increase of the number of the Operation node, and therefore can provide a reference for making network attack decision.