Abstract: A series of polycaprolactone (PCL)based composites with different weight fractions of tourmaline were prepared by a melt blending method, and then their tensile, bending and impact test bars were fabricated by a 3D printer.The mechanical properties of the resulting test bars were evaluated.The experimental results indicated that the mechanical properties of composites were improved to some extent with the addition of modified tourmaline powders, and the composites also could release negative ions.The tensile and bending strength exhibited an increasing trend until the weight fraction of tourmaline reached 5 wt %, and then they tended to decrease.However, the elongation at break and impact strength of the composites decreased with an increase of tourmaline content.The dispersibility of tourmaline powders in the PCL matrix was greatly reduced at a weight fraction over 7 wt %.The composites also presented an improvement in release capability of negative ions due to the increase of tourmaline loading.