The invention discloses a system for conveying solid raw materials by using supercritical carbon dioxide and a conveying method thereof, and relate to the technical field of energy and chemical industry. The system for conveying the solid raw materials by using the supercritical carbon dioxide and the conveying method thereof aims to achieve the technical effects that the problem that a solid rawmaterial conveying and gasifying device is low in pressure can be solved, the system steam or power consumption is reduced, and the material conveying stability is high. According to the adopted technical scheme, the system comprises a buffering device, a storage bin, a pressurizing device, a material issuing device and a material issuing conveying pipeline, the buffering device is provided with asupercritical CO2 inlet, moreover, an outlet is connected with a supercritical CO2 supply pipeline, a discharging port at the lower end of the storage bin communicates with a feeding port at the upper end of the pressurizing device, the pressurizing device is provided with a pressurized gas inlet, moreover, the pressurized gas inlet communicates with the supercritical CO2 supply pipeline, the discharging port of the pressurizing device communicates with the feeding port of the material issuing device, and the discharging port of the material issuing device communicates with a feeding port ofa high-pressure gasification furnace through the material issuing conveying pipeline.