The invention discloses a low-value large solid waste treatment method and device. The treatment method comprises smashing and iron removal, deoxidation, pyrolysis and gas-oil phase separation. The treatment device comprises a solid waste supply system, a smashing and iron removal system, a belt feeding machine, deoxidation equipment, a pyrolysis furnace and a recovery system, which are connected in sequence. According to the device and the method provided by the invention, low-value large solid waste, especially foam-containing waste, such as abandoned desks, chairs, stools and sofas, is treated by means of smashing, carbonization and pyrolysis, so that at a collection station of low-value large solid waste, the problems about quantity reduction, harmlessness and resource utilization can be solved, and meanwhile the problems about collecting and transporting the waste separately and finally treating the waste separately are solved. Therefore, the problem that waste is classified at first and then is combined in waste classification is solved from the source, and the costs of waste landfill and incineration are greatly saved.