The application of vapor-liquid dual-medium nozzle is a key factor in the tobacco feeding process. To achieve the high precision of the feeding process, it is necessary to use the existing simulation means to lay a foundation for optimizing the preliminary work of the experiment. In this work, the external mixed dual-medium nozzle was taken as the research object. Through the construction of a numerical model based on DPM, the effects of different steam inlet pressure and needle valve position on the aerodynamic performance and particle size characteristics of the nozzle atomization were studied. The results showed that the larger the flow area at the outlet of the nozzle, the closer the high-speed area of the gas flow was to the nozzle, but the maximum velocity of steam and liquid did not change greatly. At this time, the droplet injection distance changed from far to near, and the injection half angle changed from small to large. With the increase of steam pressure, the airflow velocity and the length of the high speed zone became larger. When the steam pressure was 0.1 MPa, the difference between the maximum airflow velocity and that at steam pressure of 0.4 MPa was nearly 25%. Under different pressures, the range of injection angle was small, ranging from 21.5° to 23.5°. Besides, the concentration of the spray was more concentrated, the directivity was better, and the number distribution of droplets was relatively uniform. It was favorable to control the uniformity of the spray on the surface of the tobacco leaves. For the closer tobacco wall, the nozzle structure with larger circulation cross-sectional area is conducive to evenly cover the tobacco wall. On the contrary, for the farther tobacco wall, the structure with smaller circulation cross-sectional area is suitable. Proper increase of pressure is beneficial to improve the uniformity of liquid spraying, reduce waste of liquid and improve the technological level of tobacco cutting.