Disclosed herein is a method for processing green coffee beans, including: (1) loading unroasted green coffee beans on a mesh-like plate, placing in a container the mesh-like plate having the green coffee beans loaded thereon, introducing water into the bottom of the container so as to be spaced apart from the lower surface of the mesh-like plate, and closing the lid of the container to seal the container; (2) placing the sealed container in a heating cabinet, and then steaming the green coffee beans at low temperature for 10 to 12 days while maintaining the internal temperature of the heating cabinet at 70 to 80°C; and (3) opening the lid of the container, and then drying the steamed green coffee beans for 4 to 6 days while maintaining the internal temperature of the heating cabinet at 38 to 43°C.