Abstract: Firstly,both the dynamic model and the transient energy function of a two-area interconnected system connected with the variable speed wind turbines are established.Analysis presents that inertia has distinctive effect on transient energy conversion during different oscillation stages.Secondly,this paper proposes a variable-inertia control strategy based on the cooperation of two power generation area,which can improve the transient multi-swing stability of power angle in interconnected system.Finally,an interconnected system containing four synchronous generators and two wind farms is built to verify the validity and implementability of the proposed control strategy.The results show that both regarding the frequency control ability and the transient multi-swing stability are all underpinned.