In today's general environment, the use of intelligent disinfecting robots has effectively solved the work pressure of manual disinfecting, and more importantly, ensured the safety of personnel. There is a water tank for storing liquid inside the intelligent disinfecting robot, and the function of the liquid level sensor is to monitor whether the water tank is short of liquid. When the disinfecting robot starts to work, the liquid in the water tank will slowly decrease with the sprayed mist. When the liquid drops to the detection point of the liquid level sensor, the sensor will send a signal to remind the liquid to be added, and the robot will after receiving the signal return to add liquid. It is intelligent and saves manpower and material resources.