In direct injection engines, fuel spray atomization is very important factor for the formation of fuel/air mixture, which influences on the engine performance and exhaust emissions of engine out. Especially, cavitation bubbles breaking out inside the nozzle hole have the significant role for spray atomization process. The purpose of this research is to make the effect of the cavitation on the fuel spray atomization clearly. The numerical model based on the bubble dynamics was proposed in this report, where the behavior of cavitation bubbles is treated as a function of pressure inside the nozzle hole. The prediction of bubble behavior under various conditions in the case of a single bubble was carried out by use of pressure distributions estimated through the experimental results. Primary, the processes of bubble growth and its shrinkage were calculated for each test fuel at given injection pressure. Secondary, the behavior of cavitation bubble was simulated for various initial bubble radiuses. As results of these calculations, although the position of bubble collapsing inside the nozzle hole does not coincide with experimental results, this proposed model predicts quantitatively the temporal change in bubble radius for each case.