Abstract: Based on the evolution of magneto-induced microstructure by particle dynamics simulation, the 3D geometric model was established for transversely isotropic magnetorheological elastomers(MREs). On the basis of the current two main theories for the interaction between magnetic particles, the control equations on particles were built considering the coupling effect between deformation and magnetic field. The mechanics-magnetic coupling properties were studied in the mesoscopic level by establishing the multi-particles numerical model of MREs. The comparison result between numerical model and shear experiments indicates that multipole force model is closer to the test data than point-dipoles model. The influences of magnetic flux density and particle volume fraction on magneto-induced shear modulus were also discussed, that is, the numerical model gives an excellent agreement with experiments. The optimum particle volume fraction for the largest relative magnetorheological effect is about 20%.