A millimeter wave multiple input multiple output (MIMO) dielectric resonator antenna (DRA) based on multilayer dielectric integrated groove waveguide structure is proposed in this paper. In this report, a rectangular metal cavity and defects are dug in the dielectric resonator and the ground to reduce the mutual coupling of MIMO DRA cells. This method does not need adding other structures to reduce the coupling between antenna elements, which makes the whole design simple and compact. The impedance bandwidth of the antenna ranges from 25.35GHz to 27.78GHz, the overall isolation of the antenna is no less than 21dB, and the antenna gain is 7.63dBi.