The first important factor affecting tinplate coating is that the coating must have appropriate coating conditions. The coating film applied on the surface of the tinplate by the coating machine needs to have good flowability, uniform thickness and smooth surface. When the coating speed, coating supply and baking time of the coating machine are constant, the main factor affecting the appearance quality of the tinplate coating film is the coating viscosity of the chalk material. This article aims at the control of paint viscosity during tinplate coating, and introduces it from five aspects: the influence of paint viscosity on the paint film, the measurement of paint viscosity, the paint stirring before production, the viscosity control in production, and the correct selection of thinner.