The invention discloses a deodorizing device on a water closet. The deodorizing device comprises a water closet body, wherein a through hole is formed in the lateral wall on the water closet body, a spray pipe is introduced into the through hole, a spray head facing the inner part of the water closet body is installed on a pipe opening at one end of the spray pipe, the other end of the spray pipe extends out of the through hole, a liquid-storing bottle is arranged at one side of the water closet body, a liquid aromatic is arranged in the liquid-storing bottle, a liquid-outlet pipe is arranged on the bottom surface of the liquid-storing bottle, and the liquid-outlet pipe is communicated with the extending end of the spray pipe; an air pump is arranged at one side of the liquid-storing bottle, and an air-outlet pipe of the air pump is communicated with the junction of the spray pipe and the liquid-outlet pipe. The deodorizing device has the advantages of simple structure and simplicity as well as convenience in installation; the deodorizing device is provided with a structure for spraying the aromatic, so that the odor can be removed, and the environmental hygiene is kept.