Al-Mg-Si alloy strips were prepared by the twin roll cast (TRC) in order to investigate the effect of the ripple mark observed in the strips on filiform corrosion resistance after paint. The TRC strips have 1-2 micrometers segregation layer which included high concentration iron and silicon under the surface. In the dark portion of ripple mark, the concentration of iron and silicon in the layer were high. According to the results of the cyclic filiform corrosion test, the ripple mark decreased the corrosion resistance. In the case of the scalped strip, the corrosion resistance was improved. As a result, the ripple mark with the surface segregation layers of iron and silicon decreased the filiform corrosion resistances on TRC strips.