This study aimed to make the slurry droplets atomized by the ultrasonic atomization spray coating diversion system fall on the substrate surface of hot plate stably, instead of rebound or spill due to overly high pressure or speed that causes material waste and excessive or non-uniform spray coating. The lateral movement distance of the nozzle influences the uniformity of film thickness distribution, while the lateral movement distance influences the film uniformity and the spray coating efficiency; these two are important parameters to the efficiency of ultrasonic spraying equipments. Therefore, this study conducted a simulation analysis on the atomization flow field of ultrasonic atomization diversion systems, where the distribution of atomization flow field was analyzed at different lateral movement distances of the nozzle. By evaluating the performance of thin film coating, this study attempted to find out the optimal lateral movement distance of ultrasonic precision spray coating. The simulation analysis results were tested on a real machine for validation in order to identify the reliability of the simulation. The simulation result showed that the central part of the film in the position sprayed was thicker; therefore, the nozzle moved 1 cm horizontally at 0.1m/s to thicken the repeatedly sprayed area to improve the overall uniformity of the panel. The study analyzed the spray coating thicknesses according to 16 monitoring points in the repeatedly sprayed area on the panel. According to the thicknesses of the monitoring point positions, when the area that had been sprayed once was sprayed again by the nozzle moving 1cm laterally, the uniformity of overall film on the overall panel was improved significantly.