In this study, a three-dimensional (3D) printing filament prepared from 11 poly (lactic acid) (PLA) and acetylated tannin via a twin-screw extruder was reported. 12 The impact of acetylated tannin loading content on the final properties of the 13 resulting composite materials and their 3D printability were investigated. The 14 experimental results indicate that PLA can be compounded with up to 20 wt% 15 acetylated tannin without any obvious deterioration in the tensile property. The 16 resulting composites acquired better degradation rate in aquatic system compared 17 with neat PLA, especially in alkaline medium. Moreover, all composites are printable 18 and showed generally good printing quality with brown color, however, this is 19 limited to temperatures reasonably below 220°C to avoid printing defects, especially 20 at high loadings of acetylated tannin.