Biofuel is a kind of clean energy which has good application prospects in diesel engines. The cavitation behaviors inside injector nozzle of diesel engine of biofuel and diesel fuel are numerically simulated and compared using homogeneous mixture flow model and full cavitation model. The dimensionless numbers such as cavitation number and discharge coefficient are introduced to analyze the internal flow characteristics of various fuels. The results show that the change pattern of mass flow rate and dimensionless numbers of injection nozzle are variable before and after transition cavitation. The dynamic viscosity was the primary property for the development of cavitation compared with surface tension and saturated vapor pressure.