Abstract: The structure and process of high voltage BCDMOS are studied and optimized in this paper.The BCDMOS IC includes NPN,PNP,NMOS,PMOS and high voltage LDMOS structure.The emphasis of the process is to implement these devices on one chip and optimize the structures and process of these devices.The process simulation software T-SUPREM and device simulation software MEDICI are used to optimize the devices structure and process parameters.The BCDMOS IC's which accord with the design request are taped out and the BCDMOS process are developed finally.