In this study, chitosan (CS)/expanded perlite (EP) composites with different chitosan fractions (10%, 20% and 50%) were prepared by absorbing chitosan into porous networks of expanded perlite, as a new hybrid smart electrorheological (ER) material. Structural and morphological characterizations of the composites were carried out by FTIR and SEM-EDS techniques. Also, apparent density, particle size, and conductivity of the CS/EP composites were determined. Finally, the effects of electric field strength ( E ), shear rate, shear stress, and temperature onto ER behavior of the CS/EP/silicone oil system were investigated. The CS/EP/SO ER fluid system showed reversible electrorheological activity when subjected to external electric field strength by showing shear thinning non-Newtonian viscoelastic behavior. The yield stress value reached to 1250 Pa under E = 3 kV/mm for CS/EP3 composite.