The invention belongs to the technical field of preparation of health care products, and discloses an acanthopanax root water extract and a preparation method and a control method thereof. The preparation method comprises the steps that a raw material is pre-treated, acanthopanax root is selected, washed and dried to reach the constant weight, and then smashed and passes through a 20-mesh siever;the acanthopanxa root powder is accurately weighed, distilled water is added, homogenate is performed on the mixture by a refiner, and acanthopanax root homogenous slurry is obtained; the effective ingredients of acanthopanax root are extracted through a hot water extraction method, wherein the extraction temperature is 70-80 DEG C, and the extraction time is 90-120 minutes; and extraction is conducted twice continuously, the acanthopanax root water extract is freeze-dried for stand-by application. The acanthopanax root water extract with the high oxidation resistance is prepared by taking theacanthopanax root water extract as the main accessory, and can be applied to preparing multi-functional health care drinks such as health care yogurt and health care drinks. The acanthopanax root water extract has the characteristics of being high in antioxidant activity and low in hypersusceptibility, and has the certain effect on nourishing the spleen, soothing the nerves and delaying senescence.