This study aims to numerically investigate the influence of external air flows on the water droplet dispersion under the ultra-high injection pressure conditions. The present study carried out numerical simulations with the use of the commercial computation fluid dynamics code (ANSYS FLUENT Ver. 17.0). We used SST k-w model for turbulent flow analysis and DPM(Discrete phase model) break up model for the simulation of disperse phase. The water droplets are injected to air and the external air flows are. We compared and analyzed the characteristics of dispersion distance of water droplet affected by external air flow ranging from 1 m/s to 5 m/s. The numerical analysis showed that as the external air velocity increased, the dispersion distance increased.