The invention relates to the field of additive manufacturing consumables, and discloses a polyamide 6 modified material for additive manufacturing, and a preparation method thereof. The polyamide 6 modified material comprises, by mass, 62-78% of polyamide 6 (PA6), 8-15% of glass fibers, 8-20% of a toughener, 5-10% of a compatibilizer, 0.3-2% of an antioxidant and 0.2-1% of a fiber glass exposure inhibitor. The preparation method has a simple process, and has the following remarkable modification effects: 1, the glass fibers and the toughener are added, so the mechanical strength and the toughness of the prepared polyamide 6 modified material are obviously improved, and the strengthening and toughening effects are remarkable; 2, the preferable glass fiber exposure inhibitor is added, so thefree fluidity of the material is improved, and the processing performances are improved, thereby the surface glossiness of the material is high; 3, the material has a lower shrinkage rate and a higher thermal deformation temperature than traditional nylon materials; and 4, printing verifies that silks are smoothly produced from nozzles during 3D printing, and the material has the advantages of low warping, high precision and good appearance quality, and is very suitable for producing consumables for FDM additive manufacturing.