The invention milk powder reconstituting machine with an ultrasonic automatic cleaning function. The milk powder reconstituting machine comprises a tank, a water purification system, a milk power storage bin, a quantitative milk powder adding component, a mixing bin, a milk discharge nozzle, a flowmeter, a heating module, an ultrasonic device and a control system and is characterized in that the control system is communicated with the water purification system, the milk powder storage bin, the quantitative milk powder adding component, the mixing bin, the milk discharge nozzle, the flowmeter,the heating module and the ultrasonic device through circuits, the water purification system comprises a water tank, a water pump and a filter element, the fixing bin comprises a milk powder inlet, awater inlet and a water outlet, and the ultrasonic device is arranged below the mixing bin. The milk powder reconstituting machine has the advantages that the milk powder reconstituting machine has amilk powder reconstituting function and a cleaning function, milk powder reconstituting temperature and concentration can be controlled, the cleaning times and time of the milk powder reconstituting machine can be controlled, automatic cleaning can be completed without demounting the machine, the service life of the milk powder reconstituting machine is prolonged effectively, bacterium and pollutant breeding is prevented, and sanitation and cleanliness inside the machine and milk powder drinking safety are guaranteed.