The present application provides an application of quercetin in a plant senescence accelerator, which belongs to the field of plant senescence accelerators and its application, and can prepare a plant senescence accelerator by using quercetin and apply the accelerator in practical production to accelerate the senescence process of plant particularly crop leaves. The quercetin plant senescence accelerator is prepared by mixing a quercetin mother solution with a 1/2 MS solution of 2-(N-morpholino)ethanesulfonic. In the present application, by adopting directly spraying method, the senescence process of plant leaves can be accelerated, and will not cause additional adverse reactions to plants.