The invention discloses a method for manufacturing a three-dimensional mold by using a plane design file. The method comprises the following steps: A, analyzing a whole set of color files and acquiring all texture features of the color files, and selecting a plurality of the texture features as a source file for mold design; B, extracting a grayscale file from the source file, and converting the grayscale file into a bmp format; C, converting the greyscale file of the bmp format into a three-dimensional embossment file through a fine carving software; and D, carrying out mold carving according to the three-dimensional embossment file to obtain the three-dimensional mold. The method solves the problem that when a non-texture sample such as a plane color file or a plane sample is contained in the prior art, the matching three-dimensional mold cannot be designed and manufactured.