In order to study the spraying effect of hydrodynamic ultrasonic atomizing nozzle under different spraying methods, and to investigate the practical application effect of hydrodynamic ultrasonic atomizing nozzle in agriculture, the atomization angle test and droplet size test under different spraying conditions were designed. Different spraying conditions atomization angle test and droplet size test were designed, the test results data were recorded, the pattern of change of the data was observed, and the data were fit to give the data changes in line with the functional equation; different spraying conditions and different corn leaf position droplet deposition coverage test were designed and the value of the deposition coverage of each position was recorded. The results showed that: the maximum value of the variation of atomization angle under different spraying conditions was 75.49°, and the minimum value was 14.49°; the maximum value of the variation of droplet size was 18.23 μm, and the minimum value was 4.78 μm; and the droplet deposition coverage was the highest in the mid-leaf position of the upper and lower leaves of the maize when the input air pressure was 0.3 MPa, which was 86.98% and 46.97%, respectively. Fitting the atomization angle data and droplet size data, the R2 of the binomial fit was 0.85 and 0.94, respectively, and the Adjusted R2 was 0.87 and 0.88, respectively, which made the fitting function meaningful and the fitting accuracy high. The hydrodynamic ultrasonic atomizing nozzle has a great advantage in generating small droplet sizes and performs well in deposition effect, and the experimental results can provide a reference for the research of hydrodynamic nozzles in the application technology.