A 3D printing modified polylactic acid material comprises, by weight, 70-85 parts of polylactic acid, 1-5 parts of chain extenders, 1-5 parts of cross-linking agents, 0.5-1 part of nucleating agents, 5-10 parts of polymers with low molecular weights, 5-10 parts of flexibilizers, 1-5 parts of fortifiers and 0.3-0.8 part of antioxidants. According to the 3D printing modified polylactic acid material, a low-temperature smashing hybrid reaction technology is utilized, modified processing is carried out on polylactic acid, toughness, impact strength and the heat distortion temperature for the polylactic acid are improved to a large extent, and the polylactic acid can have wider application prospects in 3D printing materials.