Abstract: In order to study the influence of air pressure and water pressure on the particle size parameters of ultrasonic atomization spray, an experimental platform was designed in this paper. Anionic surfactant rapid infiltration T was selected to configure a solution with a concentration of 0.07 % for experiment. The changes of particle size parameters of ultrasonic atomization spray under different combinations of air pressure and water pressure were analyzed. The experimental results show that the particle size parameters D₁₀, D₅₀, D₉₀, VAD, SMD and NAD decrease with the increase of air pressure, and the decrease is affected by water pressure. At the same time, the above particle size parameters also increase with the increase of water pressure, and the increase will also be affected by air pressure. The influence of air pressure on the change of droplet size is greater than that of water pressure. When the pressure changes, the change trend of particle size parameters D₁₀ and NAD is highly consistent, and the increase of particle size of D₅₀, VAD and SMD is highly consistent.