With the continuous expansion and complexity of network structure

the traditional overlapping community detection algorithm can not effectively discover reasonable community structure in large-scale network structure.Based on the concept of vertex gravity proposed in this paper

we introduce vertex cohesion and community cohesion as indexes for community structure-close internal structure and sparse external structure

and then put forward overlapping community structure algorithm OCSC.The steps of OCSC algorithm include pre-processing

core sub-mapping and core community expansion.Finally

NMI and F1Score confirm the rationality and superiority of OCSC algorithm by experimentation on synthetic and real network structures.