Fused deposition modeling (FDM) is one of the most widely used 3D printing technologies. However, the commercially available filaments for FDM are ABS, PLA, etc., which are much higher price and lacking functionality. Therefore, preparation of new filaments suitable for FDM is promising but undoubtedly challenging. Poly(vinyl alcohol)(PVA) with excellent comprehensive properties is a good biodegradable material for FDM. The key is to realize the thermal processing of PVA. In this paper, based on our former research work, the hydroxyl ionic liquid (IL) was used to control the supramolecular structure of PVA. The melting point of PVA gradually decreases from 217.3 to 146.3 along with the glass transition temperature promptly decreases from 76.61 to 11.39 upon the addition of IL, revealing that IL could act as an ideal plasticizer for PVA. The Flory-Huggins interaction parameter of PVA/IL system is at 160oC, which suggested that the binary blends of PVA/IL system was fully miscible in the molten state. The O-H stretching bands shifts to a higher wavenumber about 19cm-1 together with the striking change of peak shape in amorphous region in FT-IR, which guaranteed the interaction between IL and the hydroxyl groups of PVA. This interaction also improved the thermal stability of the PVA/IL system during processing. Then a new kind of PVA-based filament with good flowability and toughness suitable for FDM is prepared via this simple and facile strategy. The obtained PVA/IL filament exhibit excellent ionic conductivity up to 2.82×10-3S/cm with 35wt% content of IL. Furthermore, the effects of the parameters such as the layer thickness, air gap, as well as filling angle on the structure and properties of PVA/IL parts fabricated by FDM were discussed.Finally, the human jaw model and the biological scaffold with complex structure and good compressive modulus were fabricated. This work was supported by the National Natural Science Foundation of China (51433006).