A system for manufacturing graphene nanoribbon by continuous microwave is disclosed. The system comprises a microwave heating tank for heating carbon nanotube through microwave, a reaction tank for adding an oxidizing or reducing agent and a pipeline for connecting all devices of the system. A feed rate is controlled by a pump to enter raw material into the system via the pipeline, the nanotube is made to be a graphene nanoribbon by heating, adding the oxidizing agent, reheating, adding the reducing agent and reheating. Therefore, the graphene nanoribbon could be mass produced automatically in a short time.