The invention discloses a device for preparing semi-solid metal and alloy slurry, which mainly comprises an electromagnetic stirrer, an insulating layer, an external cooling controller, a valve, a draft tube, a preparation crucible, an insulating crucible cover, a standing crucible, a melting crucible and a thermocouple. The middle part of the preparation crucible is provided with an internal cooling controller, and the outer wall of the internal cooling controller forms a clearance with the inner wall of the preparation crucible. The device can be connected with a press-casting machine, an extruder, a continuous casting machine and a forging machine, wherein the press-casting machine consists of a press-casting fixed die, a press-casting movable die, an injection chamber and a punch head; the extruder consists of a right extrusion die profile, a left extrusion die profile, an extrusion cylinder and an extrusion rod; the continuous casting machine consists of a tundish, a crystallizer, a cooling water nozzle and a traction mechanism; and the forging machine consists of a forging die cavity and a forging die. The device has the advantages that the device has simple and compact structure, low investment cost and strong practicability; the temperature field and tissue of the prepared slurry are distributed evenly; the semi-solid alloy slurry is pure, does not bubble and has good self cleanness; and the device can produce large-specification semi-solid slurry or blank, and is quite suitable for the preparation and formation of the semi-solid slurry or the blank.