NOVELTY - Obtaining Artemisia sacrorum extract involves crushing mature and fresh Artemisia sacrorum, and then performing ultrasonic or reflux extraction by using 50-100% ethyl alcohol aqueous solution (10-50 times) for 10-90 minutes to obtain extraction liquid. Extraction liquid is decompressed and concentrated to obtain alcoholic extract. Alcoholic extract is mixed with distilled water (100-2000 times), extracted it 2-5 times with petroleum ether, and then standing to obtain supernatants. Supernatants are combined.    USE - Method for obtaining Artemisia sacrorum extract used for preparing acaricidal active substance preparation for killing mites (all claimed).    ADVANTAGE - The method is eco-friendly and cost-effective, and safe, enables to prevent and control Bemisia tabaci in cucumber by tearing Bemisia tabaci body wall and intestinal channel, and has social and ecological benefits.    DETAILED DESCRIPTION - Obtaining Artemisia sacrorum extract involves crushing mature and fresh Artemisia sacrorum, and then performing ultrasonic or reflux extraction by using 50-100% ethyl alcohol aqueous solution (10-50 times) for 10-90 minutes to obtain extraction liquid. Extraction liquid is decompressed and concentrated to obtain alcoholic extract. Alcoholic extract is mixed with distilled water (100-2000 times), extracted it 2-5 times with petroleum ether, and then standing to obtain supernatants. Supernatants are combined, and then decompressed and concentrated to obtain aqueous solution of petroleum ether extract. Aqueous solution of ethyl acetate (2-10 times) is mixed with aqueous solution of petroleum ether extract, and then extracted 2-5 times, and then standing to obtain supernatants. Supernatants are combined, and then decompressed and concentrated to obtain aqueous solution of ethyl acetate extract. Aqueous solution of n-butanol (2-10 times) is mixed with aqueous solution of ethyl acetate extract, and then extracted 2-5 times, and then standing to obtain supernatants. Supernatants are combined, and then decompressed and concentrated to obtain aqueous solution of n-butanol extract.