Electrorheological fluid (ERF) is a smart material which can transpose from liquid-like state to solid-like state under the action of electric field, along with this process, the physical properties of the material will be changed like apparent viscosity, yield stress and acoustic impendence. In this paper, by means of an ultrasonic shear wave reflectometry method, the transformation laws of the resistive components R and the reactive components X of the complex dynamic shear impedance, the storage modulus G(1), the loss modulus G(2), the sound velocity v are supplied.