Negative pressure sand box for evaporated pattern casting

The utility model discloses a negative pressure sand box, particularly discloses a negative pressure sand box for evaporated pattern casting, belongs to the technical field of casting production equipment, and provides a negative pressure sand box for evaporated pattern casting, which has low probability of the choking of an air exhaust system during the use process. The negative pressure sand box comprises a negative pressure sand box body with the air exhaust system, and further comprises an isolation device, wherein the isolation device covers a gas input end of the air exhaust system; and a gap allowing gas to pass is reserved between the isolation device and the gas input end.