Magnetorheological elastomers (MREs) are a kind of smart material, whose mechanical properties are controllable with applied magnetic field. Moreover, there is a greater magnetorheological effect for MREs at small strain amplitude, which has attracted more attention in the field of microvibration control. In this paper, an MRE isolator with shear-compression mixed mode was developed to suppress the high-frequency and microamplitude vibration of a precision-fabrication platform. To evaluate and characterize the dynamic behavior of the MRE isolator, experiments were conducted under harmonic load and different magnetic fields, respectively. Experiments showed that the resonance frequency of the MRE isolation system shifted from 45.82 (0 A) to 82.55 Hz (1.5 A). Meanwhile, the relative change in equivalent stiffness and damping was 175% and 216%, respectively, and the relative change in isolator force was 190% from 0 to 1.5 A. The proposed mixed mode MRE isolator effectively isolated vibration at high frequency for microamplitude.