The present invention relates to a novel extraction technology of effective components in Chinese medicine. Specifically, the present invention relates to a novel method of using ultrasound to extract an effective component kaempferol in ginkgo leaves. The method uses a design program of orthogonal experiment. Based on technical parameters of the generation method, ultrasonic intensity, functional duration, functional method, solvent type, temperature of the system, and the mixing method of ultrasound through screening and extraction process, the fresh ginkgo leaves can be prepared. The ginkgo leaves are dried at a temperature of 60 DEG C for 24 hours and crushed and screened (0.45 Mu m) to be a material. The ginkgo leaves are filled into ethanol solution of 45 percent in an ultrasonic extraction reactor; the material and solution are mixed according to a ratio (Kg: L) of 1 to 15. The generation method of ultrasound comprises a simulated audible device of ultrasound and a radial cylindrical vibration transducer. The ultrasonic power is 100W, and the ultrasonic frequency is 35 kHz. In the extraction method, the ultrasound functions once with an interval of 2 minutes; the functional time of ultrasound is 5 minutes; the total extraction time is 28 minutes; the extraction temperature is 35 DEG C; the stirring method is an air-lift stirring way; the content of kaempferol in the extraction solution is analyzed by using high-efficiency liquid-phase chromatogram. With the methods, the extraction rate of the effective component kaempferol in ginkgo leaves can reach 97.35 percent.