The invention discloses a community detection method for resisting Sybil attacks and used for a large-scale network, and the method comprises the steps: giving a social network G=(V, E), V being a node set, and E being a social link or a side set; giving a community link strength threshold t, and initializing a community link or an edge set C=null; calculating similarity indexes for nodes at two ends of the edges (u, v) in each set E, and recording the similarity indexes as suv; for each edge (u, v) in the set E, if suv is not less than t, adding the edge (u, v) into the set C; and calculatingall connected sub-graphs in the set C, wherein each connected sub-graph is a community. According to the invention, community detection of different granularities in a large-scale network can be realized, Sybil attacks can be effectively resisted, and the community security is improved.