This device extracts the air between the sand particles in the specialized sand box through vacuum pumping, forming the sand particles in the sealed sand box, making the sand mold have a certain compactness, and the interior is in a vacuum negative pressure state. When pouring the mold, vacuuming can accelerate the exhaust speed and reduce the exhaust volume, reduce the interface pressure between the metal liquid and the model, accelerate the advancement speed of the metal liquid flow front, improve the filling ability of the liquid flow, and reduce the carbon black defects on the surface of the casting; It can also suppress the combustion of foam molding materials, promote their gasification, improve the environment, increase the fluidity and formability of the metal liquid, and make the casting contour clearer and more distinct.