A chemic etching to manufacture the double-sided connected one-sided flexibility printed circuit board belongs to the field of printed circuit, the one-sided basic material is non-glue one-sided copper foil, the thickness of the basic material is 0.0125 millimeter -0.050 millimeter, the thickness of the copper foil is 0.018 millimeter -0.035 millimeter, the manufacture of the polyimide etching protecting layer is cover a protecting layer on the polyimide surface, use the hot water process the polyimide film before etch it, put the polyimide film into the etch liquid, take the polyimide film out of the etch liquid and clean it in the water with about 80-95 centigrade, clean it again to wipe off the polyimide etching protecting layer, that is fit for manufacture the fine line broad or space between of the double-sided connected one-sided flexibility board, choose the one-sided basic material directly, reduces the technical process.