By means of the interface reactions of CH3CSNH2?H2NCSCSNH2?H2NCSNH NH2 on zinc plate surface, Insoluble coordination compound films are formed with a metallic luster of various colours changing in accordance with the reaction t ime. The films are functional finishing layers, not only possessing decorative p roperties, but improving the brightness and cleanliness of the metal surface. Tr eatment of the zinc plate or zinc oxide substrate with the thioamide compounds r esults in colored surface films. Because of the interface reactions caused by th ioamide compounds, they are comparable with each other in reactivity. During the interface reaction, the deprotonated and undeprotonated thioamide behave differ ently. The compositions and structre of the surface films have been determined o r postulated based on XPS and AES measurement. The data show conclusively that t hioamide compound layers on zinc plate are responsible for the color of the film s.