With the fast integration of so much distributed power sources and electricity storage system devices, the 10kV distribution network becomes more resiliency. After losing the superior power during fault period, it can continue to supply some important users by the access to distributed generation. However, there will be more and more constraints, liking the sequential operation of energy storage, radial topology of distribution network, no allowed secondary outage and load supply priority. They make the island partition a difficult problem. Therefore, this paper proposes a fast island partition method considering energy storage in smart distribution network. Its characteristic is that it can use power and power balance information to establish a mixed integer knapsack model of island division considering time series fluctuations on both sides of source and load, and quickly give an island division scheme with clear physical meaning. With proposed method, the simulation analysis of the improved PG&E 69-bus system is carried out to verify the effectiveness of the proposed method.