Dual Connectivity(DC)technology is an innovative technology,which can meet the growing demand of high data rate transmission in 5G Heterogeneous Network(HetNet).In 5G ultra-dense HetNet,DC handover is a further optimization and development of traditional mobile network handover.Therefore,based on the general concept of DC technology,this paper designs 5G Non-Standalone Access(NSA)architecture and Standalone access(SA)architecture.At the same time,in order to ensure the continuity of 5G ultra-dense HetNet service and avoid frequent handover between small cells and ping-pong effect,a handover program based on DC is designed.