The invention discloses a millimeter wave antenna system, which comprises a metal frame with an antenna gap, a high-dielectric coverage layer, a signal transmission unit, a signal receiving and sending component and an intermediate frequency and base band processing unit, wherein the high-dielectric coverage layer is arranged on the outer side of the antenna gap; the signal transmission unit is arranged on the inner side of the antenna gap; the signal receiving and sending component is electrically connected with the signal transmission unit; the intermediate frequency and base band processingunit is electrically connected with the signal receiving and sending component; and the high-dielectric coverage layer, the antenna gap and the signal transmission unit jointly form the dielectric resonant antenna array of the millimeter wave antenna system. The antenna system provided by the invention has the characteristics of small land occupation, more correctable factors, high working efficiency and the like. The invention also provides another millimeter wave antenna system, a phased array module, a metal shell, a method for eliminating the backward radiation of the antenna radiation gap of the metal shell, a user terminal and millimeter wave communication equipment.