A photocatalyst sterilization device includes a housing, wherein the housing includes a first receiving chamber and a second receiving chamber that are in communication with each other, the first receiving chamber receives a photocatalyst layer and a light source assembly configured to irradiate the photocatalyst layer, the second receiving chamber receives an axial-flow fan； and an air inlet and an air outlet are defined in the same surface of the housing, one of the air inlet and the air outlet is corresponded to the first receiving chamber in position, the other one of the air inlet and the air outlet is corresponded to the second receiving chamber in position, and a direction in which the axial-flow fan suctions air via the air inlet is parallel to a direction of irradiation of the light source assembly.
