Method and system for verifying making time of a file by computer

The present invention is providing a method and a system for verifying making time of a file by computer. The method comprises: calling TWAIN protocol interfaces of a scanner for obtaining original color data both of an object file and a sample file, wherein making time of said sample file is known; sampling color points of said original color data of said object file thereby calculating color index data of said object file; and sampling color points of said original color data of said sample file thereby calculating color index data of said sample file; and comparing said color index data of said object file with said color index data of said sample file, and determining making time of said object file based on said known making time of said sample file. In accordance with the present invention, the sample file or the object file can be verified without damaged for the reason of analyzing color of said file by computer. By use of the computer system for sampling, analyzing, carrying out the result the present invention has reduced the influence of man-made factor so that it provides more reliable security to such result.