According to the characteristic of AC-excited variable speed constant frequency wind turbine， a grid voltage orientation vector control strategy is used for doubly-fed induction generator（DFIG）. Firstly， this paper studies the running characters of DFIG， and the principle of DFIG under no-load cutting-in condition. Then according to the mathematical model of DFIG under no-load cutting-in condition， this paper proposes a higher-order sliding mode control for the model. Finally， a comprehensive system simulation on the no-load operation is carried out and the following situations are studied: before cutting-in， the transient process at the cutting-in moment and the DFIG tracks the maximum wind energy after cutting-in. The simulation results validate the proposed method.