A detergent additive box configured to mount on a washing machine, wherein the detergent additive box is a closed box structure having a cavity; the detergent additive box is provided with a one-way ventilation valve and a liquid outlet ; an on-off valve is arranged on the liquid outlet ; a suction device is arranged in the detergent additive box ; an inlet of the suction device is communicated with the cavity, and an outlet of the suction device is communicated with an inlet of the on-off valve ; characterized in that , the one-way ventilation valve comprises a ventilation element and an opening and closing element , an air vent is provided on the ventilation element , the air vent passes through upper and lower end faces of the ventilation element , a connection hole connected to the opening and closing element and a ring groove assisting in sealing the opening and closing element are coaxially arranged on the ventilation element , the opening and closing element comprises the opening and closing portion and a connection portion , the connection portion is provided with a ring convex plate and a transition section , a hollow hole is formed inside the transition section extends and passes through the opening and closing portion , when air pressure in the detergent additive box is reduced, the opening and closing portion deforms, with a tail end leaving the ring groove , the air vent is on, and when the air pressure in the detergent additive box is equal to the external air pressure, the opening and closing portion restores the original shape, with the tail end inserting into the ring groove to seal the detergent additive box , the air vent is off. the detergent additive box is provided with a one-way ventilation valve and a liquid outlet ; an on-off valve is arranged on the liquid outlet ; a suction device is arranged in the detergent additive box ; an inlet of the suction device is communicated with the cavity, and an outlet of the suction device is communicated with an inlet of the on-off valve ; characterized in that , the one-way ventilation valve comprises a ventilation element and an opening and closing element , an air vent is provided on the ventilation element , the air vent passes through upper and lower end faces of the ventilation element , a connection hole connected to the opening and closing element and a ring groove assisting in sealing the opening and closing element are coaxially arranged on the ventilation element , the opening and closing element comprises the opening and closing portion and a connection portion , the connection portion is provided with a ring convex plate and a transition section , a hollow hole is formed inside the transition section extends and passes through the opening and closing portion , when air pressure in the detergent additive box is reduced, the opening and closing portion deforms, with a tail end leaving the ring groove , the air vent is on, and when the air pressure in the detergent additive box is equal to the external air pressure, the opening and closing portion restores the original shape, with the tail end inserting into the ring groove to seal the detergent additive box , the air vent is off. <EOS>