Abstract: Compared with the conventional pressure atomization and pneumatic atomization, effervescent atomization has the advantages of high efficiency, economy and environmental protection, which has attracted the attention of various fields. In this paper, a series of experiments were carried out on a variable nozzle internal swirling effervescent atomizer, and the effects of the working parameters, hole structure and mesh number on the flow and spray characteristics were discussed. The results show that flow characteristics of the atomizer with different hole structures are basically the same. The change of the air-liquid ratio results in the change of the liquid mass flow rate under the same working pressure. Flow characteristics are not affected by the cutting screen, while the addition of the cutting screen induces 3%–7% attenuation of the spay mass flow rate of under the same working condition, and the smaller the cutting screen aperture is, the greater the reduction of the spray mass flow rate is. The distribution of spray particles presents a single peak structure, and the median mean diameter of the spray decreases with the increase of the working pressure or air-liquid ratio. Under the same spray energy consumption, the special-shaped hole structure is more helpful to improve the spray performance. The cutting screen is beneficial to the spray performance, but the choice of the mesh aperture should be made based on the atomizer structure, the working pressure and other comprehensive judgment; in addition, the addition of the cutting screen reduces the axial velocity of the spray mainstream to a great extent.