Magnetorheological Elastomers (MREs) are a type of magnetorheological (MR) material, which is a combination of magnetic particles and a soft elastic matrix. As a new class of intelligent material, MREs possess controllability, reversibility, rapid response as well as stability under magnetic fields. Thanks to these characteristics, MREs have found a wide range of applications in many fields, such as vibration absorbers, absorber isolation, pumps, and soft robots in recent years. All these applications will be discussed in this review. Additionally, this paper will describe the effects of particles, matrices, additives, and synthesis on the performance of MREs.