Blends of poly(lactic acid) (PLA) and a series of renewable bioelastomers (PLBSIs) were fabricated through melt blending to improve the toughness of PLA. Benefiting from reasonable macromolecular design, the introduction of lactic acid in PLBSIs not only increases the compatibility with PLA but also helps PLBSIs turn from crystalline plastic to amorphous elastomer. The increasing compatibility was evidenced by the decreasing particle size of PLBSIs in PLA and the better toughening effect of elastomer than that of plastic was characterized by the thermal tensile test. Thus, the super toughened PLA blends were obtained and exhibited maximum elongation at break of 324 % and the impact strength of 35.7 KJ/m2, 50 and 15 times higher than neat PLA, respectively. Excellent performances in 3D-printed tensile tests imply the toughened PLA was ideal 3D-printing ink. The super toughened PLA will eliminate the brittleness of PLA for wide application and hold great potential for both engineering and biomedical applications.