The utility model discloses a sand box for casting, and relates to the field of casting equipment. Each of the upper box and the lower box comprises an outer frame, an inner frame, a top plate and anejection mechanism; the side wall of the inner frame is fixedly connected with the side wall of the outer frame; a bottom plate of the outer frame is located below a bottom plate of the inner frame and does not make contact with the bottom plate of the inner frame, a top plate is slidably connected into the inner frame, a plurality of centrosymmetric through holes are formed in the bottom plate ofthe inner frame, connecting columns slidably penetrating through the through holes are fixedly connected to the bottom of the top plate, an ejection mechanism is arranged on the bottom plate of the outer frame, and moving components of the ejection mechanism are fixedly connected with the connecting columns. The ejection plate is pushed by the ejection mechanism to eject the sand mold, so that the operation is convenient, and the labor efficiency is greatly improved; the integrity of the sand mold is ensured, and castings cannot be lost.