The invention discloses a defoaming injection device and a delayed coking drum device. The defoaming injection device comprises a defoaming supply component and a spraying part, wherein the spraying part is mounted in a coke drum; the defoaming supply component is used for supplying a defoaming agent for the spraying part; and the defoaming agent sprayed from the spraying part is capable of completely covering the top surface of coke in the coke drum. By adopting the defoaming injection device disclosed by the invention, when crude coke in the coke drum meets a normal height position, the defoaming supply component is powered on to provide the defoaming agent to the spraying part, and the defoaming agent sprayed from the spraying part is capable of completely covering the top surface of the coke in the coke drum, sufficiently contacts with a foam layer in the coke drum and is dropped down as droplets, so that the foam layer can be well pressed, the height of the crude coke in the cokedrum can be increased, and the utilization efficiency of the coke drum can be improved.