Abstract: A kind of multi-master and multi-functional surveillance system based on CAN bus was designed. Following the discussion about the main issues of CAN bus system design, a mixed bus architecture, CAN associated with RS-485/422 was introduced. The core design was C8051F SOC MCUs and CP2102, a new USB to UART bridge. The result of implementation showed that this system successfully solved the main issues, for example, the bottleneck in data transmission, data collision and synchronization.The high real-time ability and stability made this design suitable for various long-distance real-time surveillance networks.