Automatic defrosting cover

The automatic defrosting cover comprises an outer heat preservation cover, an inner heat preservation cover, a control module and a temperature and humidity sensor. The outer heat preservation cover is slidably connected to the outer side of the inner heat preservation cover, and the outer heat preservation cover and the inner heat preservation cover are sequentially provided with an outer box layer, a heat insulation layer, a heating layer and a heat preservation layer from outside to inside. The heating layer is an electric heating wire spirally arranged between the heat insulation layer and the heat preservation layer. A narrow-end-up drainage groove is formed in the top end of the outer heat preservation cover, the cross section of the drainage groove is sequentially divided into a conical confluence section and a direct flow section, a plurality of air inlet fans are transversely arranged on slopes on the two sides of the inner side of the conical confluence section, and a plurality of exhaust fans are t