Aiming at the problem that most mapping algorithms based on virtual Software Defined Network （vSDN） do not fully consider the correlation between nodes and links， a vSDN mapping algorithm based on network topology segmentation and clustering analysis was proposed. Firstly， the complexity of physical network was reduced by the topology segmentation method based on the shortest hop count. Then， the request acceptance rate of mapping algorithm was improved by the clustering analysis method based on node topology and resource attributes. Finally， the nodes that do not meet the link requirements were remapped， by dispersing the link constraints to the bandwidth resources of nodes and the degrees of nodes to perform the consideration with constraints， so that the mapping process between nodes and links was optimized. Experimental results show that， the proposed algorithm can effectively improves the request acceptance rate of virtual network mapping algorithm based on Software Defined Network （SDN） architecture in physical networks with low connectivity probability.