Abstract: A method and a device for treating waste printed circuit boards with molten tin include process of throwing printed circuit boards into a molten tin bath in treating furnace, letting the boards proceed crashing, stirring and carbonizing treatment for separating copper foil, thermosetting plastic and glass fiber. Then these three kinds of materials are respectively separated from each other by taking advantage of their different specific gravity and collected in separate tanks to recover copper and other metals from the waste printed circuit boards.