Abstract: For problem of bad effect of falling dust because of insufficient pressure of water spraying system outside heading machine fuselage, a high pressure spraying device for falling dust of heading machine was designed. The device mixes high pressure airflow with waterflow to inject water mist particle with good atomization effect and large covering area at a high speed, and can greatly reduce the dust concentration on working face. The practical application shows that the effect of falling dust of the device is remarkable, and total dusting efficiency is above 80% in inlet and return airflow at ten meters away from tunneling working face.