The invention provides a mechanical lifting device and method for releasing a high-temperature melt. The device comprises a releasing mechanism, a connecting mechanism, a sealing mechanism and a powermechanism, which are arranged on a heating system located in a pressure container in sequence, wherein the releasing mechanism comprises a crucible plug; the lower end of the crucible plug is taperedand the upper end of the crucible plug is in thread connection with a guide rod; the crucible plug is made of a non-conducting material and the plug is prevented from being subjected to induction heating; the connecting mechanism comprises the guide rod which is in thread connection with the crucible plug, and three twisting rods which are connected in sequence and are used for transforming horizontal displacement of a screw rod into vertical displacement of the guide rod; the power mechanism comprises a hand wheel and is used for providing power to the lifting device through rotating the hand wheel. The invention also provides the lifting method of the device. According to the mechanical lifting device and method, provided by the invention, reliable releasing of the melt can be effectively realized; the device has a simple structure and normal utilization of other equipment is not influenced, so that a feasible method is provided for researching a melt layering behavior of a nuclearpower plant reactor.