Abstract: Aiming at the strip-like gray-white color difference defects appearing on SUS430 J1L ultra-pure ferritic stainless steel strip used in luxury automotive trim after finishing rolling, experimental measurements confirmed that the primary cause of these color defects is the higher surface roughness of the affected strip areas compared to normal regions. Surface observations further revealed a higher density of scratches in the defect regions. By comparing the distribution of roll surface discoloration with the positions of color-difference defects on the strip, and by analyzing the formation mechanism of roll surface discoloration, it was clarified that the surface roughness variation of the strip was closely related to the lubrication state in the roll bite during cold rolling. The difference in lubrication state was further attributed to the non-uniform distribution of Cr oxide films with different compactness on the strip surface after bright annealing. To effectively eliminate this type of color-difference defect, the uniformity of the Cr oxide film was improved by strictly controlling the annealing dew point temperature below-60 ℃ and maintaining a cooling rate not lower than 35 ℃/s. Meanwhile, the oil film uniformity during rolling was enhanced by reducing the rolling speed, increasing the rolling force, and selecting a low-viscosity rolling oil with sufficient extreme-pressure additives. These measures effectively mitigated the color-difference defects on the surface of ultra-pure ferritic stainless steel and improved the surface quality of the stainless steel strip.