The invention discloses an opening and closing mechanism of a cavity cover, which comprises a control unit, a driving mechanism, a transmission mechanism, two actuating mechanisms and an equipment cavity with a cavity cover, wherein the transmission mechanism comprises a transmission shaft, a speed reducer, a worm, a worm gear, a connecting shaft and a supporting body in a hollow structure, the supporting body is fixedly connected with one side wall of a cavity body, the connecting shaft penetrates through the supporting body and is parallel to the cavity cover, both ends of the connecting shaft are respectively connected with the two actuating mechanisms, the worm gear is fixed on the connecting shaft and is positioned in the supporting body, the worm is arranged in the supporting body and is vertically engaged with the worm gear, an output shaft of the speed reducer is connected with one end of the worm, an input shaft is connected with one end of the transmission shaft, the other end of the transmission shaft is connected with the driving mechanism, the control unit controls the movement of the driving mechanism, and the driving mechanism synchronously drives the two actuating mechanisms by the transmission mechanism so as to realize the opening and the closing of the cavity cover. The invention has simple structure, convenient operation, labour saving, high safety and accuracy, can not deform the cavity cover easily and ensures the high vacuum degree of vacuum equipment in OLED production.