The invention relates to a crystalline silicon rough grinding and fine grinding integrated machine and a use method thereof, and belongs to the field of crystalline silicon machining devices. The crystalline silicon rough grinding and fine grinding integrated machine comprises a base and a slide rail. The slide rail is arranged on the base. In the length direction of the slide rail, a rough grinding area, a crystalline silicon transfer mechanism and a fine grinding area are sequentially arranged. The crystalline silicon transfer mechanism is arranged between the rough grinding area and the fine grinding area. The rough grinding area and the fine grinding area are each provided with a grinding feeding work table mechanism used for clamping crystalline silicon, and at least two grinding headfeeding assemblies. The grinding feeding work table mechanisms are located on the slide rail and are connected with the slide rail in a sliding manner. The grinding head feeding assemblies located inthe rough grinding area and the fine grinding area are symmetrically arranged on the two sides of the slide rail, and a grinding passageway which allows the crystalline silicon to pass through and grinds the crystalline silicon is formed. According to the crystalline silicon rough grinding and fine grinding integrated machine and the use method, rough grinding machining and fine grinding machining are conducted on the crystalline silicon through the rough grinding area and the fine grinding area correspondingly; and rough grinding machining and fine grinding machining can be conducted on different crystalline silicon at the same time, and the work efficiency is doubled.