In order to enhance the stability of ginger oil emulsions, ultrasound-assisted emulsification method was used for the preparation of ginger oil emulsions in this paper. The optimization was based on single factor and response surface optimization experiments. Four main factors in the preparation process (amount of emulsifier, ultrasonic power, time and temperature) were investigated. According to the visual analyses of the result, the optimum condition was obtained. Based on the optimal condition in the response surface optimization experiments, the preparation process was then conducted under ultrasonic emulsification. (The effects of ultrasound amplitude and irradiation time on the encapsulation process were also studied). The microemulsion type, grain size, and phase transition temperature were used to characterize the resulting sample. Finally, the average particle size of ginger oil nano-emulsion attained 94.49 nm in the condition of ultrasonic power 250W, ultrasonic time 5.8 min, ultrasonic temperature 50 °C, emulsifier concentration of 1.0 g / 10 ml, implying that the ultrasonic emulsification technology can solve the difficulty of macromolecular oil microemulsion preparation.