In this article, the systematic design, construction, and testing of a novel tunable isolator based on magnetorheological elastomers in coupling shear-squeeze mixed mode have been studied. The influence of magnetic particle volume fraction on field-induced properties of magnetorheological elastomer isolator is studied, and the performance of vibration mitigation of magnetorheological elastomer isolator is evaluated experimentally. The results show that the frequency-shift property of magnetorheological elastomer isolator is linearly proportional to the magnetic particle volume fraction and applied current, and vibration mitigation capacity of magnetorheological elastomer isolator is remarkably enhanced by increasing the applied current. The design of magnetorheological elastomer isolator in coupling mixed mode may provide a new insight for using magnetorheological elastomers in vibration reduction applications.