In view of the conventional distribution system service restoration failing to consider the condition of important load, an improved smart distribution system restoration service, which includes DG islanding technique and bases on the relationship between supporting feeders and the active load of the failure one-level nodes, is proposed. First, when determining area of the DG islanding, the strategy proposed in this paper refers the relationship between the supporting feeders and the capacity of the DG, then using breadth-first search method to find the optimal DG islanding plan. Second an improved bread-first search algorithm is used to establish the power supply adjacency, and determines the service restoration for the failure one-level nodes, then The Hungarian algorithm is used to determine the service restoration for the failure second-level nodes and the failure third-level nodes. Analysis of case study verifies the feasibility of the proposed algorithm.