In this paper, a distributed control model based on CAN bus protocol is put forward to solve the problems of dissimilar bus units, various signal lines and jamming signal existing in the centralized control model of underwater detection system (UDS). According to the requirements of modular, low power, real-time communication in the design of system, this paper introduces the hardware and software systems design based on 16-bits SCM MSP430 used as the core controller. Through hardware-in-the-loop simulation, it is proved that the design based on CAN bus has good flexibility and compatibility, not only provides long-time underwater protection, but also provides technical support for all-purpose design of UDS in future.