Cinnabar stick sequence checking is one of the most important parts of document formation timechecking technology. As the number of cases involving ink-jet printed documents increases, in order to effectivelysolve the problem that it is difficult to test the sequence of ink in ink-jet printing documents, the principle of thin-film interference is applied to the sequence of ink documents, and exploring a new feature in cinnabar stick se.quence. In view of the printer type, the seal oil type, the seal material, the light and so on, the thin film interferencephenomenon to the ink time sequence influence is sought and the ink time sequence phenomenon formation reasonis analyzed. Through observing the appearance of yellow-green interference fringes under different conditions by mi.croscope examination, a comprehensive comparison and analysis is made. The results show that the thin film inter.ference phenomenon is more obvious in the document which is printed first and then stamped than in the documentwhich is stamped first and then printed. It can be concluded that the thin film interference phenomenon is valuablefor cinnabar stick sequence checking, and can provide reference for the sequence judgment of printing documentsand seals.