A new detecting method of pulse laser discrete scratching is presented to estimate the bond strength of film-substrate interface and a device is designed to achieve the automation of discrete scratch. Through detecting typical coatings failure the database is established. The optimal algorithm method is applied to the laser system in which it immediately approaches the power density range of laser with coating failed. Through the power meter detecting infrared beam reflective surface of the coating surface morphology of coatings,detection system obtains characteristic parameters;which will be compared with the failure database to arrive next point laser output power. Asymptotic approximation is used to determine the fact coating failure threshold and the design achieve intelligent discrete scratches.