The invention relates to a supervision on-duty control system and a supervision on-duty control method for time-sharing operation of an underwater robot/submersible. A supervision on-duty control circuit module is connected through a CAN bus with an autopilot, a buoyancy adjusting control device, a water surface communication positioning unit and a satellite positioning device, and controls the work of the autopilot, the buoyancy adjusting control device, the water surface communication positioning unit and the satellite positioning device. A depth meter and an altitude meter are connected through serial communication ports with the supervision on-duty control circuit module, and respectively sample and send depth information and altitude information to the supervision on-duty control circuit module for monitoring. A leakage detection sensor is connected directly to the input port of the supervision on-duty control circuit module to monitor the leakage state in real time. Through the system and the method, long-time underwater detection task of an underwater robot/submersible can be completed to the greatest extend under the condition that the underwater robot/submersible carries limited energy.