In the present paper, mechanical properties test and morphology observation，the effect among electric field, magnetic field and electromagnetic field, shear ratio on the Ni/TiO2/Urea core-shell particles electrorheological fluid properties were studied. It is found that with increasing electric field, magnetic field and shear ratio in the same composition electrorheological fluid, the property of electrorheological fluid can be increased. However, there is a critical value for shear ratio. When shear ratio is larger than 20s-1, the property of ER is nearly certain value for same composition ER fluid. Electromagnetic field reciprocal effect can increase the properties of ER fluid, and make the particles chain become thicker and interweaved each other.