The invention, which relates to the technical field of automatic control systems, discloses an automatic control system for hot water releasing in a bathroom. The system comprises a controller for receiving working data of a hot water pump. The controller controls the water supply amount of the hot water pump to a water replenishing tank and opening/closing of a water outlet solenoid valve of thewater replenishing tank. A detection unit installed in the water replenishing tank transmits detection data to the controller. The controller controls working time of the hot water pump by an actuator. According to the invention, the water outlet solenoid valve is controlled by setting corresponding water outlet time after controller installation, so that a problem of water wasting caused by operation inconvenience of the staff member and forgetting of closing can be solved; and after water use time predetermination, the centralized water usage need is met and people use the system conveniently.