A non-contact ultrasonic atomization based on the Fabry–Pérot resonator is proposed to obtain atomized droplets with a reduced droplet diameter and concentrated droplet distributions. To better understand the mechanism inside the acoustic chamber, the acoustic–fluid interactions are numerically explored inside the Fabry–Pérot resonator to achieve the precise modulation of droplets. The influence of the acoustic chamber's geometry and the ultrasonic properties on the atomized droplet diameter and distributions is investigated, aiming to establish matching relationships between the atomized droplet diameter and the geometry of the acoustic chamber. The dynamic behaviors of droplet breakup are observed with a high-speed camera to reveal the atomization mechanism of liquid droplets in high-intensity acoustic fields. The experiments demonstrate that the proposed non-contact atomization can achieve atomized water droplets with a median diameter of ∼24 μm, providing an alternative to ultrasonic spray.