The atomizing process at the nozzle during application of casing materials to tobacco was investigated in order to more uniformly spray casing on tobacco and to further improve the efficiency of tobacco casing. The atomization characteristics, such as atomization cone angle of the nozzle, atomized particle size and particle size distribution, were studied by digital characterization with a high-speed camera and image recognition processing technology on a 30 kg/h atomization test platform. Moreover, the division of the atomization zone at the nozzle in various sections was studied on the basis of characteristic droplets that could be absorbed by tobacco more easily. The results showed that: (1) the atomization cone angle, the atomized particle size and particle size distribution could be visualized in digital form by a high speed camera and image recognition processing technology; (2) the particle size range for characteristic droplets was determined as being 0.05 mm to 0.8 mm; (3) on the basis of characteristic droplets, the atomization zone of the nozzle was divided into three sections, namely an injection section, an atomization section and a diffusion section; (4) the results of this study provide a new method and technology for improving the efficiency of tobacco casing.