Disclosed is a detergent additive box. The detergent additive box is a closed box structure having a cavity inside. 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. The detergent additive box of the present disclosure cooperates with a switching mechanism of a washing machine and a feeding pipeline of the washing machine to realize automatic drainage and multi-time drainage, so that the detergent additive box does not need to be mounted at each time of washing.