A neurosurgical ultrasonic focusing assisted three-stage atomization cooling and postoperative wound film forming device has a transducer housing and a nozzle, wherein a horn is arranged in the transducer housing, at least two layers of piezoelectric ceramic sheets are arranged at the top of the horn, an electrode sheet connected with an ultrasonic generator is arranged between two adjacent layers of piezoelectric ceramic sheets, the bottom of the transducer housing is of a hemispherical structure, and a plurality of piezoelectric elements connected with the ultrasonic generator are arranged inside the hemispherical structure; and the nozzle is arranged at the bottom of the horn and connected with a medical nanofluid storage cup, compressed gas can also be introduced into the nozzle, and an electrode is also arranged inside the nozzle.