In this paper the design of a single vector six-component wind tunnel balance cali-bration system is introduced,which can calibrate piezoelectric balances by multi component cali-bration method adopting “unload”weight to accomplish instantaneous loading.The weight hits some rigidity object in movement by invariableness speed to accomplish unloading.And the weight can become a single vector load by adj usting the posture of the balance and hanging posi-tion in loading device.It can meet the need of super high-speed wind tunnel experiments.The structure of the system consists of balance posture adjustment equipment,weight loading equip-ment and unloading equipment by collision,and so on.The measurement system and control sys-tem are also expounded in the paper.Because of the simple structure and less error resources,the equipment has advantages of high efficiency and high calibration precision.