The Article introduces the structual characteristic of flexible Coupling，explains their application and mechanism at multi-component force calibration device. When the multi-component calibration device force to transducer, some transmutation will be take placed between them, the veracity will be affected. The function of flexible Coupling is get over the effect. The article introduces technique design, applications effect and validate examination of flexible Couplings which are used in the multi-component force calibration device.