The invention discloses a paper money authentic identification method and a device. The method comprises the following steps: intercepting a zebra crossing area image in an infrared transmission picture of the paper money to be detected; removing a safety line contained in the zebra crossing area image, and forming an initial zebra crossing image; executing the binarization processing to the initial zebra crossing image, and marking at least one connected region in the image after the binarization processing; and according to the geometrical characteristic of at least one connected region, determining the true and false of the paper money to be detected. Through the technical solution, the method is capable of realizing the real-time counterfeit currency detection, shortening the time of the counterfeit currency detection, and simplifying the effect of the authentic identification process.