Full-mold casting method of resin sand without vent hole

The invention discloses a full-mold casting method of resin sand without a vent hole. The full-mold casting method comprises the steps of manufacturing a pattern and a casting system, molding, smelting casting, forming and cleaning, wherein working allowance is preset on the upper surface of the manufactured pattern in the steps of manufacturing the pattern and the casting system, and no vent hole is formed in the molding step; the casting system comprises a plurality of sprues provided with pouring cups at the top ends and arranged vertically, the volume of the pouring cup is more than that of the sprue, the bottom of the sprue is communicated with a cross gate parallel to the length direction of the pattern, the lower end surface of the cross gate is leveled with the bottom surface of the pattern or is slightly higher than the bottom surface of the pattern, the length of the cross gate is 95% of the length of the pattern, and a plurality of ingates communicated with the pattern are arranged on the cross gate at intervals; and molten metal is poured by the plurality of pouring cups simultaneously during casting. According to the full-mold casting method, no vent hole is formed, pattern burning cannot happen during casting, no harmful gas is generated and the environment protection effect is achieved.