We made use of compression-testing machine and LCR digital electric bridge to apply pressure stress and record the value of impedance which controlled by a computer throughout the whole testing process. Four stress loading methods were designed for testing, and a systematic research had been done with a scanning frequency at 1KHz for silicon/FeCuNbSiB amorphous powder compound films. It has been found that rubber matrix film is a kind of elastomer, which has some elastic deformation phenomenon such as elastic hysteresis and ratcheting. The radical reason of stress impedance (SI) effect is the internal relations between elastic deformation and impedance change. Deformation of elastic film will directly influenced the impedance, and the function of stress applied on the film will directly cause elastic deformation, thereby indirectly cause the change of impedance. Result shows, stress impedance effect is relevant to the recover process of elastic deformation. In the course of stress loading, the longer deformation recovered, the more indistinctively changed of impedance.