A series of Cr-doped multiferroelectric FeBiO 3 nanoparticles were synthesized via a facile sol gel method. The resultant Cr-doped FeBiO 3 was characterized by means of different techniques, such as scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and electrorheological (ER) tests. Under an external electric field, electrorheological properties of the suspension containing such Cr-doped and undoped FeBiO 3 particles were investigated by steady shear experiments. It was found that the suspension of Cr-doped FeBiO 3 particles possesses a better ER effect than that of pure FeBiO 3 particles. Furthermore, different Cr-doped concentration plays an important role on the ER behavior. Combining the dielectric analysis, the enhanced ER effect of Cr-doped FeBiO 3 suspension can be attributed to the improved interfacial polarization.