A design of wind power generation system with Double Fed Induction Generator (DFIG) in isolated system is proposed, with an Energy Storage System (ESS) inserted in the direct current side of the back-to-back converter and the capacity change of the load side converter to amplify the ESS’s ability to stabilize the power fluctuation. Power decoupling control strategy is applied for the rotor-side converter of the system to achieve maximum power tracking. Constant voltage and frequency control strategy is applied for the load-side converter to achieve the voltage and frequency constancy in isolated system. A phase synchronization control strategy based on frequency disturbance is applied when the isolated system parallels in the grid. A simulation model is developed and the results show the effectiveness of the control strategy for the stable operation of isolated system and the rapid synchronization when the system parallels in the grid.