The design of electrical layout is a key elementin the offshore wind farm planning. We present a novel electrical layout design optimization method for off shore wind farms in this paper. The proposed method can be used to generate the network model based on fuzzy c-means(FCM) and binary integer programming (BIP) methods. It can automatically allocate wind turbines to the near estsubstations and obtain the topology structure of cablesutilized to connect wind turbines or turbine and substation.The objective of this optimization is to minimize the investment costs of cable connection and the transmission power losses. The results of case study clearly demonstrated the feasibility of the proposed method and showed that it can be used as a reliable tool for electrical layout design of off shore wind farms.