A method for inserting information into a 3D structure and recognizing information in a non-destructive method is provided. A 3D printing method according to an exemplary embodiment of the present invention includes: generating a tag having specific information recorded thereon to be inserted into a 3D structure, and printing the tag on the inside of the 3D structure while printing the 3D structure. Accordingly, since the tag having information recorded thereon is printed on the inside of the 3D structure when the 3D structure is printed by a 3D printer, it is impossible to forge/falsify information.