NOVELTY - Double-layer flexible copper-clad plate is prepared by cleaning and drying flexible polyester substrate, soaking cleaned substrate in amino-substituted silane solution for 0.5-2.5 hours, cleaning and drying substrate; soaking substrate in mercapto-substituted silane solution for 3-6 hours, cleaning and drying substrate; and soaking polyester substrate processed by sulfhydrylation in chemical plating liquid of copper for plating for 0.5-6 hours at 20-80 degrees C, taking substrate, cleaning and drying substrate.    USE - Method for preparing double-layer flexible copper-clad plate (claimed) used for flexible circuit board and flexible electronic apparatus e.g. flexible field effect transistor, flexible solar battery and flexible light emitting diode.    ADVANTAGE - The method produces copper-clad plate having light and thin body, and high ductibility, binding intensity, electric conductivity and planeness, and acidity, alkalinity and organic solvent resistance.    DETAILED DESCRIPTION - Preparation of double-layer flexible copper-clad plate comprises:    (A) cleaning and drying flexible polyester substrate, soaking cleaned substrate in amino-substituted silane solution for 0.5-2.5 hours, taking substrate, cleaning and drying substrate to obtain substrate with surface processed by hydroxylation;    (B) soaking substrate in mercapto-substituted silane solution for 3-6 hours, taking substrate, cleaning and drying substrate to obtain substrate with surface processed by sulfhydrylation;and    (C) soaking polyester substrate processed by sulfhydrylation in chemical plating liquid of copper for plating for 0.5-6 hours at 20-80 degrees C, taking substrate, cleaning and drying substrate to obtain flexible copper-clad plate, with chemical plating liquid of copper of de-ionized water as solvent, and concentrations copper sulfate at 4-8 g/L, potassium sodium tartrate at 5-10 g/L, sodium citrate at 8-12 g/L, disodium versenate at 4-8 g/L, dimethylamine borane at 4-8 g/L, and sodium hydroxide at 1-2 g/L.