For active distribution network, its characteristics can be described as multi-source, multi-segment, multi-branch, bidirectional power flow, bidirectional fault current, weak-infeed and so on. In this case, the selectivity and sensitivity of traditional over current protection scheme cannot be ensured. It is necessary to provide more effective protection methods. This paper introduces a current differential protection scheme based on positive sequence fault component (PSFC) into active distribution network, and discusses its application principle and implementation technology. For different structure of feeders, the corresponding criterions and threshold setting rules are provided. In view of the current condition of distribution network, a self-synchronization scheme using fault signal is proposed and realized. And the communication protocols used for data exchange of differential protection based on peer to peer communication is discussed according to the new development of distribution automation communication architecture. Finally, the proposed protection prototype is developed based on a platform of intelligent distribution terminal, and the test results have verified the feasibility of the protection scheme.