ABSTRACT: A continuous feeding and discharging system for solid material under high pressure is provided. The system includes a feeding assembly, a high pressure vessel, and a discharging assembly. The feeding assembly includes a raw material hopper that feeds solid raw material, a CO2 feeder that feeds dry ice, and a mixer that mixes the solid raw material with the dry ice to form an impermeable mixture. The high pressure vessel performs an extraction process under a supercritical condition to extract soluble components from the solid raw material. The discharging assembly includes a discharging extruder that receives the solid residue discharged from the high pressure vessel, a binder liquid feeder that feeds binder liquid to mix with the solid residue to form a uniform mixture and compacts the mixture to form impermeable pellets of residue, and a discharging valve that discharges the impermeable pellets of residue from the discharging extruder.