A novel displacement remoter measurement utillizing Dopples effect was proposed in this paper. The Doppler shift of differential structure was analyzed theoretically. The double-beam differential optical system with a optical-acoustic modulating structure, big aperture collecting backward scattering light, and compensating the losing signal by computer tracking software was designed. The displacement measurement of paper and rough mental surface at a distance of 10 meters has been achieved with an accuracy of ±0.5%.