According to the cleaning demand of cold rolled oil on DC04 cold rolled strip surface, we use COMSOL Multiphysics software to establish the temperature field distribution and oil stain removal process model of nanosecond pulse laser cleaning oil stain on DC04 cold rolled strip surface. The results show that when the spot radius is 80 μm and the laser energy density reaches 3.48 J/cm², the oil can be basically removed. Then, a nanosecond pulsed laser is used to clean cold rolled oil on the surface of cold rolled strip steel. The results show that when the laser energy density exceeds 3.48 J/cm² and the laser spot overlap rate is 50%, the oil pollution can be removed, which is consistent with the simulation results. In addition, the influence of laser spot overlap rate on laser cleaning effect is also studied. The results show that the laser energy density should be increased to 4.47 J/cm² when the spot overlap rate is reduced to 37.5%. Therefore, nanosecond pulsed laser can effectively clean the cold rolled oil on the surface of DC04 cold rolled strip without causing obvious damage to the surface of the strip, which provides a reference for determining the process parameters of nanosecond pulsed laser to clean other kinds of materials.