The reliability and security of small wind turbines is attracting more and more attention with the use of wind turbines on the rise, i.e. the overspeed control in the high winds. The paper proposes an overspeed control method through matching of rotor and generator. The power-rev graph of rotor with different wind speeds is divided into three parts, i.e. upgrade area, peak, downgrade area. The different area presents different matching characteristic of rotor and generator. Two 300W/24V wind turbines are designed and tested, which have different matching characteristics. The theory and experiment both indicate: if a special matching of rotor and generator happens, the wind turbine can complete overspeed control by itself no introducing any more components.