When the fireproof color steel plate is used in shearing, a kind of surface defect often appears, that is, surface pressure spot defect. The defect is that the coating surface is slightly deformed due to the coiling tension when the coating is baked and rolled after cooling. Sometimes the surface appears rough, showing the visual pressure spot shape. What causes this?With the extension of the storage time of the fireproof color steel plate, the slight spot defects will disappear gradually, and can be eliminated by heating. However, even if the above measures are adopted, the more serious defects can not be eliminated, thus affecting the use of users. Spot pressing is a kind of defect in the production process of fireproof color steel plate. If the causes and influencing factors of this kind of defect are found in the production process, it needs to stop for many times to check and arrange, which will affect the production plan and increase the production cost. Therefore, it is necessary to simulate, copy and evaluate the defects in the laboratory to find out the causes of the defects and the factors influencing the defects.