Transient flash-boiling ofpentane play a key role in the process of asphalt spray granulation.However, none of precise model can simulate the multiphase flow which is the thermal non-equilibrium phase changing process.According to the mechanism of mass and heat transfer in pressure depress induce to phase change, pentane flash-boiling model has been built and implanted into the platform of a commercial computational fluid dynamics (CFD) code Fluent 6.122.The simulation result of pentane flash-boiling flow in nozzle was compared with theoretical calculation result and the agreement was rather satisfactory.Comparisons of the flash-boiling flow in the different nozzles show that the nozzle with coin structure can avoid pressure suddenly reducing, which decrease the vaporization rate of pentane in nozzle and prevent obstruction of nozzle from happening.