Multi-layered two- and three-component magnetorheological elastomer (MRE) isolators were designed using a one-dimensional phononic crystal (PC) model. The elastic wave propagation properties of the two kinds of structures were studied using the transfer matrix method. Results show that the elastic band gap (EBG) position can be regulated by an external magnetic field and that the width of EBGs can be adjusted by varying component thickness. The three-component structure, which includes lead, can better tune the EBGs of MRE vibration isolators.