Abstract: The present invention is to disclose a method of hidden patterns and characters, which comprises the following steps of: 1. finishing an original document after a printing design is formed; 2. transforming the original document into a digital document; and 3. performing an anti-counterfeiting treatment to the digital document; 3-1. single-selecting a color plate from a design pattern file of the digital document; 3-2. forming a filter file of the digital document; 3-3. performing a graphic arts lining treatment, which comprises: aligning and overlapping the filter file and the selected color plate and transforming a pattern of the color plate with a darkness/lightness ratio into a linear filling pattern with a corresponding thickness/thinness ratio; and 3-4.