Negative pressure layered isolation animal cage

The utility model discloses a negative pressure layered isolation animal cage which comprises a draught fan, an air inlet, two high-efficiency filters, layered independent isolation space and an air outlet. A first high-efficiency filter is mounted between the air inlet and the layered independent isolation space; a second high-efficiency filter is mounted between the air outlet and the layered independent isolation space; an air outlet of the draught fan, the air inlet, the layered independent isolation space and the air outlet are communicated; the layered independent isolation space is provided with delivery windows and operation openings with gloves and sleeves. Every two layers of the layered independent isolation space are combined. A motor drive shaft is connected with an intake valve and an exhaust valve and the air flow can be adjusted by adjusting motor voltage or by adjusting the size of the intake valve and the exhaust valve. The negative pressure adjustment of the cage can be achieved through the