A 3D printing device integrating material supplying, fluxing and crystal leveling assistance comprises a support, a material bin, a first forced feeding mechanism, a second forced feeding mechanism, an auxiliary heating head and a crystal leveling assistance vibrating head, wherein the material bin, the first forced feeding mechanism, the second forced feeding mechanism, the auxiliary heating head and the crystal leveling assistance vibrating head are all mounted on the support. The material bin, the first forced feeding mechanism and the second forced feeding mechanism are sequentially connected. A nozzle is connected to a discharging outlet of the second forced feeding mechanism, and a heating device is arranged at the discharging outlet. The auxiliary heating head and the crystal leveling assistance vibrating head are arranged at the bottom of the support and located in front of and behind the nozzle respectively. The device is easy to operate, stable, reliable and convenient to maintain; the compactness of formed workpieces in the 3D printing process is improved, interlayer bonding of the formed workpieces is good, and the cost is low; through material selection, size changes and process adjustment of corresponding components, the device can be suitable for fused deposition of powder materials of different types.