The embodiments of the present disclosure provide a 3D printing apparatus, a production line using the apparatus, and a cyclical printing method thereof. The 3D printing apparatus includes a frame assembly, and a powder spreading unit, a powder spreading movement system, a powder supply device, an inkjet unit, an inkjet movement system, a working box, a transfer unit, an inner lifting mechanism, an outer lifting mechanism, an accessory unit and an auxiliary unit that are mounted on the frame assembly. In the embodiments of the present disclosure, a plurality of 3D printing apparatuses are arranged in a centralized manner to form a production line system with high printing efficiency, wherein the plurality of 3D printing apparatuses and baking devices are planned and arranged in a centralized manner, and form a closed-loop production system by means of a plurality of conveying and transferring routes, which reduces the idle time of some of the apparatuses during production and improves the use efficiency of the apparatuses, thereby realizing 3D printing of high efficiency.