The invention discloses a method and a device for judging hob wear conditions of a harvester, which relate to the field of agricultural machinery. The method comprises the steps of: acquiring torque of a shredding roller of the harvester at a preset time interval, and humidity of the harvested material after shredding; judging torque variation trend and humidity variation trend; and determining the hob wear conditions of the harvester according to the torque variation trend and the humidity variation trend. The method and the device for judging hob wear conditions of the harvester can effectively avoid the packaging compactness and final fermentation degree of the harvested material from being affected by the wear of the hob, and can improve the working efficiency of the harvesting operation. Compared with the method of manual judgment, the method disclosed by the invention can accurately judge whether the hob has worn out, and has the advantages of high judgment accuracy and high practicability.