This paper presents the study of rheological and mechanical properties of MR elastomers fabricated using small and large particle. Analysis indicated that MR elastomers fabricated with bimodal particles at a specific particle ratio ingredient show enhanced MR effect compared with those fabricated with monoparticles. MR elastomer samples were fabricated by using small and large particles with sizes of 5m and 50m respectively. Their rheological and mechanical properties were characterized with a MR rheometer. Experimental results agree well with the analysis.