Three kinds of FPC own characteristics; ① sided flexible board is the lowest cost, while the electrical performance requirements of the PCB. When single wiring, single-sided flexible board should be selected. Chemically etching a layer having a conductive pattern, the surface of the flexible insulating substrate a conductive pattern layer is rolled copper foil. ② sided flexible board is electrically conductive pattern on both sides of each layer of the insulating base film made of an etching. Metallized hole pattern of insulating material on both sides of the connection form a conductive path, to meet the flexibility of design and functionality. The cover film can protect single, double wire and indicating element sited. ③ multilayer flexible board is single-sided or double-sided flexible circuit 3 or more layers laminated together, through the drill larvae L, the formation of metallized plated holes between different layers form a conductive path. Thus, without the use of complex welding process. Multilayer circuit has great functional differences in higher reliability, better thermal conductivity and is more convenient assembly performance. In designing the layout, it should take into account the interaction of the assembly size, number of layers and flexible