The invention relates to a semi-solid rheological molding device for a metal part. The semi-solid rheological molding device is characterized by consisting of a pouring system, a fusant cooling system, a cooling plate adjusting mechanism, a size insulation system, a structure supporting and sealing system, a multichannel temperature monitoring system, an inert gas protection system and a die-casting system. The semi-solid rheological molding device solves the problem that size is difficult to store and transport in the semi-solid rheological molding process, and realizes the integration of semi-solid rheological pulping and molding; the device has a simple and compact structure, saves the space and does not need to make any improvement on the prior die-casting equipment; and a pulping process is simple, has a short flow, is convenient to monitor, can effectively protect gas, prevent oxidation, improve the quality of a fusant, and reduce factors influencing heat exchange of the system, is favorable for controlling the thermal balance of the system and improving the precision and the stability of temperature control, reduces thermal loss, is favorable for energy conservation and consumption reduction, and is in particular suitable for small-and-medium-sized enterprises. The semi-solid rheological molding device has wide application prospect including semi-solid blanking and rheological die-casting of aluminum alloy, magnesium alloy and tin alloy.