The invention discloses a method and device for protecting carbon products from silicon infiltration in the graphitization process. The device comprises a graphitization furnace. A heat insulation layer is formed by a mixture of metallurgical coke powder and quartz sand in the furnace; graphitized coke particles with a thickness of 160 mm are utilized to separate the heat insulation layer and products needing to be graphitized; and the metallurgical coke powder is laid between the graphitized coke particles and the heat insulation layer at the top to form a blocking layer with a thickness of 20 mm. Through the arrangement of the blocking layer, silicon dioxide in quartz sand in the heat insulation layer is prevented from coming into contact with the products needing to be graphitized through gaps between the graphitized coke particles, and the silicon infiltration phenomenon resulting from the reaction in a high temperature environment is avoided. The heat insulation layer is the mixture of the metallurgical coke powder and the quartz sand; when the metallurgical coke powder is used to form the blocking layer, no new material is needed, materials can be taken locally, and the operation is convenient.