Disclosed is a humidity detector, which includes a light emitting part, a light receiving part and a humidity detecting part. The light emitting part and the light receiving part are positioned at two sides of the humidity detecting part along a first direction, and light emitted by the light emitting part is received by the light receiving part after passing through the humidity detecting part. The humidity detecting part includes a light transmittance adjustable part and a humidity sensitive deformation part, the humidity sensitive deformation part is configured to deform along with the change of the ambient humidity, and the light transmittance adjustable part is configured to change the transmittance to the light under the deformation effect of the humidity sensitive deformation part.