an atractylodes lancea extract feed additive and a preparation method thereof are provided . the atractylodes lancea extract feed additive takes an atractylodes lancea extract and a carrier as raw materials . the atractylodes lancea extract is prepared by the ultrasonic auxiliary water extraction . the preparation method of the present invention has less raw material waste , high activity component content in the extract and acquisition rate of the extractum , which facilitates improving the effect efficiency and reducing production cost . the atractylodes lancea extract feed additive as a natural plant feed additive is capable of reducing malaria incidence , restoring consciousness and relieving uneasiness , and diuretically swelling .