During the cold rolling of thin strip on the 1220mm five-stand tandem cold mills, scratch marks occur on the surfaces of strip and work roll. The surface quality of strip is degraded and the roll wear increases, which resulting in significant economic loss. In this paper, the mechanics of strip scratch marks was studied by carrying out both field experiments and theoretical analysis. Slippage Factor (SF) and Scratch Mark Factor (SMF) were presented to indicate the conditions of strip scratch marks. Meanwhile, mathematical models and simulation code were developed to optimise the rolling schedules and to improve the scratch marks. The practical application of the developed models to the 1220 mm five-stand tandem cold mills verifies the effectiveness of the developed models. The mathematical models can be applied to other similar tandem cold mills.