Abstract: To meet the demand of the raster-vector conversion,a structural element method is proposed which can automatically acquire roads from highway color maps.The proposed method has two key steps.First,all region pixels are recognized automatically,and then set the colors of the recognized pixels as white.Then all roads are acquired by completely eliminating noise of the region such as text and icons.Our method is applied to a class of highway color maps to verify its effectiveness.The superiority of our method is illustrated through the comparison with other existing method.