The invention discloses a method and a device for determining importance of communication nodes in a power communication network. The method comprises the following steps: acquiring an undirected graph G(V, E) corresponding to the power communication network, wherein V is a set of the communication nodes in the power communication network, and E is a set of communication links in the power communication network; acquiring undirected subgraphs corresponding to the communication nodes in the undirected graph, wherein the undirected subgraph corresponding to any communication node is a graph obtained in a way of removing any communication node and a communication link taking any communication node as a starting point or an end point from the undirected graph; and determining the importance of the communication nodes according to a minimum spanning tree value of the undirected graph and minimum spanning tree values of the undirected subgraphs. Through adoption of the method and the device, the technical problem that the importance of the communication nodes in the power communication network cannot be calculated accurately in the prior art is solved.