Abstract: Poly(lactic acid) (PLA) was toughening modified using three tougheners of poly(butylene adipate-co-terephthalate) (PBAT), poly(ethylene-butyl acrylate-glycidyl methacrylate) (PTW) and thermoplastic polyurethane(TPU), all with the mass fractions of 5%, 10%, 15%, respectively, and then the wires were prepared and directly formed by fused deposition modeling (FDM) technique. The effects of the tougheners on the property of wires and printed parts were studied. The results show that all three tougheners had the good compatibility with PLA. The flowability of PTW modified PLA wire was the best and increased with the increase of PTW content. With the increase of toughener content, the tensile strength of the modified PLA printed part decreased while the impact toughness increased. The 10wt% PTW modified PLA wire was the most suitable for FDM printing because of the appropriate flowability; the surface of the printed part was smooth.