Caitu coating thickness is color-coated product testing important indicators caitu points, which directly affect the performance of other color-coated, it is accurate or not is not only affect the quality of color-coated, but also affect the cost of production . Cold rolling mill paint color coating production line is an estimate of the amount of color-coated by applying the amount of production functions to estimate the amount of the reserve according to the paint, arrange production plan. In actual production, the real amount of the coating is detected by laboratory results to determine the thickness of the coating. Recently, cold rolling mill production line paint painted estimated amount falls far short of the real amount, in order to ensure the accuracy of the test results of the coating thickness, color coating production line to ensure normal production, many factors affect the coating thickness is discussed. In this paper, a large number of test data, color-coated substrate, a passivation film weight and detection methods, such as several aspects of the analysis, to improve the color-coated coating thickness accuracy of the test results provide a basis for the implementation of standards GB / T12754-2006 color coated steel sheet and strip, and GB / T13448-2006 Test method of color coated steel sheet and strip. Four kinds of color-coated coating thickness detection method GB / T13448-2006 prescribed method for magnetic gauge, micrometer method, drilling destructive microscopy and optical microscopy methods. This experiment mainly domestic major steel mills before the widespread use of three kinds of methods. The new color-coated roll coater coating machine is the key equipment of printing color coated roll coating process, a higher yield using two sets of multi-color coating unit fine coater to shorten the replacement of paint and coating roller cause downtime. Has developed a new coating machine: Features a double-coated fine coater head, that the next two painted head layout, with hydraulic drive to replace the coating roll, about 2 seconds to complete the change of color, its small footprint; single slide coating machine, which eliminates the gap between the rolls of multiple errors piled higher than the traditional type slide coating machine precision coating, the coating thickness can implement the best control, can save a lot of paint. Some roll coater also added Dr. knife used in the production of high quality color coated. Caitu slitting, Jinhong Run steel (certified), color-coated by Boxing Xingfu Town 金宏润 Steel Industry and Trade Ministry. Boxing Xingfu Town 金宏润 Steel Industry and Trade Ministry (www.bxjhr.com) (www.bxjhr.com) is a leader in Binzhou, board (with) wood, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. In Jinhong Run Steel leadership with the staff warmly welcome all inquiries negotiations to create a better future for the steel Jinhong Run.