The explosive growth of mobile data brings the problems such as base station overload

the scarcity of spectrum resources and so on.The traditional cellular network can not satisfy the requirement.In order to obtain the throughput and user density enhancement

heterogeneous cellular network become the inevitable choice.In this paper

we assume that SeNB is based on the coverage of S-MeNB and T-MeNB simultaneously

and based on the dual-connection technology in heterogeneous network.Then we design the process of S-MeNB switching to T-MeNB.In order to verify the success of the design of the dual connection handover process

we present a scheme of combining TTCN-3

which verifies the rationality and feasibility of the process design.