When mining the key-nodes from large-scale networks, the traditional methods are poor efficiency. To address this defect, a new algorithm, which based on communities, is presented for mining the key-nodes. First, it improved the community detection algorithms, and then put forward an algorithm based on degree centrality of the node for mining the key-nodes. The experimental results show that when applying the new algorithm to mine the key-nodes from communities, not only the influence degree of mining is guaranteed, but also the efficiency is improved significantly.