— A method to fabricate circuits on the cloth, planar fashionable circuit board (P-FCB), is proposed. And its applications such as fabric passive elements, user I/O interface, and the fabric package are introduced. The electrical and the mechanical characteristic analysis of P-FCB and the system integration methodology establishment improve the system performance and productivity. A complete wearable system is implemented by P-FCB technology for the continuous sweat monitoring and the RFID tag antenna applications. Keywords- Fabric circuit board, capacitive sensor, sweat monitoring