Abstract: This paper reports the characteristics of electrorheological fluids (ERF) which were prepared by silicone oils add starch and methyl-cellulose respectively. The dynamic behavior and static yield stress were measured. The effects of percent by weight, shape, particle size of material has been investigated. When ERF's elasticity viscosity and electric field relative low, ERF's dynamics behavior may be described by Bingham model. Shear stress versus electric field square and percent by weight are in direct ratio.