The utility model provides a particle aggregation treatment device which comprises a treatment cavity and a module for generating ultrasonic waves, wherein air flow outlets are formed in the end surface of one side of the treatment cavity; air flow inlets are formed in the end surface of the other side of the treatment cavity; ultrasonic wave radiation through holes, through which ultrasonic waves enter the treatment cavity, are formed in the side surface of the treatment cavity. According to the particle aggregation treatment device, the treatment cavity is used as a treatment space for performing ultrasonic wave treatment on a to-be-treated air flow such as air flowing into the treatment space; when the ultrasonic waves pass through an air medium with suspended particles, the suspended particles start vibrating together with the air at different relative vibration speeds because of different sizes, collided and adhered to one another, and enlarged and cannot vibrate along with the ultrasonic waves any longer but moving irregularly, continuously colliding and adhering to one another to be enlarged, so that the effect of aggregation is achieved, and the purpose that the particles are filtered by using filtering units with less grades is finally achieved.