The invention discloses a preparation method of artemisinin, wherein the preparation method comprise the steps: with artemisinic acid as a starting material, obtaining dihydroartemisinic acid under the hydrogen/metal catalyst action, then oxidizing dihydroartemisinic acid into arteannuic acid dihydrogen peroxide by hydrogen peroxide in the presence of sodium molybdate, and finally acting with oxygen under the catalysis of copper trifluoromethanesulfonate, to obtain the target product artemisinin with high yield. Compared with the prior art, the preparation method has the following advantages:the used reagents are cheap and easy to get, the synthetic route is short, the reaction selectivity is high, the preparation process is environmentally friendly, the operation and post-processing aresimple, the total yield is high, and the preparation method is suitable for industrialized production.