TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: In step (i), the acid containing ethanol solution contains 10-60 vol.% of water and 0.02-0.2 mol/l of acid. The acid is sulfuric acid, hydrochloric acid or acetic acid. In step (i), the volume (ml) of the acid containing ethanol solution used for extraction every time is 3-10 times of the dry weight (g) of the R. vomitoria root powder. In step (ii): the volume (ml) of the non-polar macroporous absorption resin is 40-50% of the dry weight (g) of the R. vomitoria root powder for absorption of the concentrated extract solution with the non-polar macroporous absorption resin at normal temperature; the volume of water is 1-5 times of that of the non-polar macroporous absorption resin for washing the resin with water; the volume of 40% ethanol is 2-5 times of that of the non-polar macroporous absorption resin for eluting the resin with 40% ethanol; and the volume of 80% ethanol is 2-5 times of the non-polar macroporous absorption resin by volume for collecting the eluate A1, then eluting the resin with 80% ethanol and collecting the eluate B1. In step (ii), the 40% ethanol contains 59 vol.% of water and 1 vol.% of hydrochloric acid; and the 80% ethanol contains 19 vol.% of water and 1 vol.% of hydrochloric acid. In the step (iii), the volume (ml) of the weakly acidic cation exchange resin used for absorbing each part of eluate is 20-30% of the dry weight (g) of the R. vomitoria root powder for absorbing the concentrated eluates A1 and B1 with a weakly acidic cation exchange resin at normal temperature; the volume of water is 1-5 times of that of the weakly acidic cation exchange resin for cleaning the resin with water; the volume of 50% ethanol is 3-5 times of that of the weakly acidic cation exchange resin for eluting the resin with 50% ethanol and collecting elates A2 and B2. In step (iii), the 50% ethanol contains 45 vol.% of water and 5 vol.% of hydrochloric acid. The 15%, 20%, 25%, 30%, 35%, 40%, 55% and 95% ethanol solutions in step (iv) respectively contain 95%, 90%, 85%, 80%, 75%, 70%, 65%, 60%, 45% and 5 vol.% of water, and contains 0.01 vol.% of trifluoroacetic acid. In step (iv), the concentrated acid is concentrated sulfuric acid or hydrochloric acid. Preferred Method: The step (iv) comprises: respectively regulating the pH of the collected eluates A2 and B2 to about 3, decompressing, heating and concentrating, respectively absorbing the concentrated eluates A2 with C18 reverse phase chromatography media at normal temperature, where the volume (ml) of the C18 reverse phase chromatography media is 10-20% of the dry weight (g) of R. vomitoria root powder; then sequentially eluting the media with 5%, 10%, 15%, 20% and 95% ethanol solutions, where the sum of volumes of the ethanol solutions is 10-30 times of the volume of the C18 reverse phase chromatography media; then collecting the eluates A3 in sections, absorbing the concentrated eluates B2 with C18 reverse phase chromatography media at normal temperature, where the volume (ml) of the C18 reverse phase chromatography media is 10-20% of the dry weight (g) of R. vomitoria root powder; then sequentially eluting the media with 15%, 20%, 25%, 30%, 35%, 40%, 55% and 95% ethanol solutions, where the sum of volumes of the ethanol solutions is 10-30 times of the volume of the C18 reverse phase chromatography media; and then collecting the eluate B3 in sections. The step (iv) for collecting the eluates in sections means that the eluting time or eluting volume is divided into several sections, and 1 part of eluate is collected in each section of eluting time or eluting volume. The step (v) for adding the organic solvent for crystallization comprises: for the yohimbine, ajmaline or serpentine, adding methanol, stirring the mixture for dissolving the solids, where the amount of methanol is enough to dissolve all solids, then adding ether being 2-5 times of the volume of methanol, stirring the mixture, placing the mixture at 0-5 degrees C, separating out crystals, and removing the mother liquor to obtain the crystals; for the reserpine or rescinnamine, adding ethyl acetate to be stirred for dissolving the solids, where the amount of ethyl acetate is enough to dissolve all solids, then adding methanol being 2-5 times of the ethyl acetate by volume, stirring the mixture, placing the mixture at 0-5 degrees C, separating out the crystals, removing the mother liquor to obtain the crystals; and placing the obtained crystals into a drying oven for drying at 40-50 degrees C to have a constant weight. In the step (v) for measuring the content of each alkaloid in eluate A3 and B3 collected in sections by the HPLC, if the purity of some alkaloid is not high enough and the purification is desired, the eluates containing the alkaloid to be purified again in the eluates A3 or B3 are combined as A2 and B2, and the step (iv) is operated once again. The decompressing, heating and concentrating step is performed at 45-65 degrees C under a vacuum degree of 0.08-0.10 MPa. Only 40% ethanol eluate A1 is used for performing the operations in the steps (iii) to (v) to sequentially obtain the A2 and A3 as well as the final alkaloids yohimbine and ajmaline. Only 80% ethanol eluent B1 is used for performing the operations in the steps (iii)-(v) to sequentially obtain the B2 and B3 as well as the final alkaloids serpentine, reserpine and rescinnamine.