TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: In the step (i), the reduction reaction is preformed in presence of hydrogen as reducing agent, at hydrogen pressure of 1-100 bar, preferably 50 bar, and the reaction temperature of -50 degrees C to 60 degrees C, preferably 25 degrees C. In the step (i), the reduction reaction is preformed at -50 degrees C to 60 degrees C in presence of nickel chloride and sodium borohydride used as reducing agent. The reduction reaction temperature is -40 degrees C. In the step (ii), the oxidation reaction of dihydro-artemisinic acid and the corresponding peroxides of dihydro-artemisinic acid are carried out in presence of an alkali, metal catalyst and an organic solvent. The purification process is performed by column chromatography or recrystallization process by using organic or inorganic solvent. Preferred Components: In the step (ii), the metal catalyst used during the oxidation reaction, is salts of calcium, sodium, molybdenum, chromium, lanthanum, cerium, tungsten, scandium, titanium, zirconium, vanadium or its oxides. The mol ratio of catalyst and dihydro-artemisinic acid is 1:1-100. The metal catalyst is molybdenum acid, chromium trioxide, chromium chloride, potassium dichromate, calcium chloride, calcium hypochlorite, tungsten oxide, sodium tungstate, scandium oxide, scandium nitrate, scandium chloride, zirconium dioxide, zirconium oxychloride, vanadium oxide, sodium vanadate, cerium nitrate, ceric sulfate, cerium oxide, cerium chloride, cerium hydroxide, lanthanum cerium chloride, lanthanum cerium carbonate, lanthanum oxide, lanthanum chloride, lanthanum hydroxide, lanthanum nitrate, lanthanum carbonate, lanthanum fluoride, lanthanum hexaboride, sodium hypochlorite or sodium perchlorate. In the step (i), the alkali is an inorganic alkali or an organic alkali, where the mol ratio of dihydro-artemisinic acid and alkali is 1:1-100. The alkali is cesium carbonate, potassium carbonate, sodium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide, potassium hydroxide, lithium hydroxide, triethylamine, diisopropylethylamine, pyridine, imidazole, 1,8-diazabicyclo (5.4.0) undec-7-ene, 1,4-diazabicyclo(2.2.2)octane, dicyanodiamine, tetramethylguanidine, sulfaguanidineor or N,N,N',N'-tetramethylethylenediamine, which can be used as inorganic alkali or an organic alkali during the reaction.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The reaction solvent is methanol, ethanol, propanol, isopropanol, n-butanol, isobutanol, tetrahydrofuran or toluene. In the step (i), the mol ratio of dihydro-artemisinic acid and peroxide is 1:1-100, where the peroxides can be used in all the reactions. The peroxide is meta-chloroperoxybenzoic acid, hydrogen peroxide, tert-butyl hydroperoxide, peroxyacetic acid or trifluoroperacetic acid. The hydrogen peroxide is 30%, 50% or 70% aqueous solution of hydrogen peroxide. The organic solvent is acetone, tetrahydrofuran, diethyl ether, dichloromethane, chloroform, acetonitrile, toluene, methanol, ethanol, isopropanol, dimethylformamide (DMF), dimethyl sulfoxide (DMSO) or benzene. The acid is a Bronsted acid or Lewis acid, where the mol ratio of acid and peroxides of dihydro-artemisinic acid is 1:1-100. The acid is p-toluenesulfonate, trifluoroacetic acid, acetic acid, camphorsulfonic acid, copper (II) trifluoromethanesulfonate, aluminum trichloride, ferric trichloride, copper chloride, copper oxide, ferric oxide, copper/Dowex resin or copper (I) thiophene-2-carboxylate. Preferred Method: In the step (ii), the amount of organic solvent used during the oxidation reaction, is 50-10000 ml/mol, and the reaction temperature is -78 degrees C to 60 degrees C. The solvent is acetone, tetrahydrofuran, diethyl ether, dichloromethane, chloroform, acetonitrile, toluene, methanol, ethanol, isopropanol, petroleum ether, cyclohexane, n-hexane, DMF, DMS0, n-propanol, n-butanol, ethyl acetate or benzene. Preferred Method: In the step (iii), the acid-catalyzed rearrangement reaction of peroxides of dihydro-artemisinic acid is carried out in presence of organic solvent and under oxygen atmosphere to obtain artemisinin, where the reaction temperature is -78 degrees C to 60 degrees C.