Abstract: Polylactic acid (PLA)/poly(3-hydroxybutyric acid-co-3-hydroxyvalerate) (PHBV) blends were prepared by melt blending, and then the 3D printing standard samples were prepared by a fused deposition modeling (FDM) method. The effect of mass ratio of PLA and PHBV on the 3D printing performance was investigated. The results indicated that the PLA/PHBV blends were completely incompatible. The tensile strength of the blends and their 3D printed specimens decreased compared to pure resin, but their elongation at break increased with the addition of PHBV. The bending strength the impact strength of the blends were found to increase at first and then to decrease. The injection molded samples achieved the maximum tensile strength up to 43.31MPa and the maximum elongation at break of 5.37%. The 3D printed specimens exhibited the maximum tensile strength up to 49.16MPa and the elongation at break of 7.41%. Scanning electron microscopy revealed that there was a typical "island" distribution in the quenched sections of the blends and their 3D printed specimens, in which the PHBV phase was uniformly dispersed in the PLA matrix. With the increase of PHBV content, the cross section of the injection molded samples became rougher and the gap between the layers of the 3D printed specimens became smaller. This led to an increase in filling rate and an improvement in bonding performance.