Flash-boiling occurs when fuel in injected into a combustion chamber where the ambient pressure is lower than the saturation pressure of the fuel. In the present study, the sub models of flash-boiling spray are constructed. The sub models consider the bubble nucleation, growth and disruption in a nozzle orifice and injected fuel droplets. Therefore, the model is implemented into KIVA3V and the spray characteristics of multicomponent fuel with and without flashing is numerically investigated. In addition, these numerical results are compared with experimental data which were obtained in the previous study using a constant volume vessel. The flashing spray characteristics from numerical simulation qualitatively show good agreement with the experimental results. Especially, it is confirmed from both the numerical and experimental data that flash-boiling effectively accelerates the atomization and vaporization of fuel droplets.