Abstract: The ionic liquids Emim OAc was used as biocatalyst medium and extraction agent in enzymatic hydrolysis process with the ultrasonic aimed to improve the extraction efficiency of ginger oil. The experimental results showed that the enzyme activity was higher for 15% EmimOAc/buffer biphasic system than for pure buffer system,but the enzyme activity decreased in higher ionic liquid's concentration. What's more,the effect of ultrasonic power,ultrasonic time and liquid-solid ratio on the extraction rate of ginger oil were investigated.The optimum conditions were shown as follows EmimOAc concentration was 15%,ultrasonic power was 200 W,ultrasonic time was 20 min,liquid-solid ratio was 15∶1. The extraction of ginger oil was 1.39%.