The invention relates to a method for preparing an antimalarial active compound artemisinin through direct column chromatography and belongs to the field of drug preparation techniques. The method comprises the steps of: weighing 1 part (by weight) of artemisia annua leaf powder which is sieved by a sieve with the particle size of 100 meshes, weighing 0.7-1.4 parts (by weight) of silica gel or alumina which is sieved by a sieve with the particle size of 80-100 meshes, mixing the artemisia annua leaf powder and the silica gel or alumina, and grinding uniformly; coating the substance, obtained in the last step, in a glass chromatography column containing 0.8-5.0 parts (by weight) of silica gel or alumina which is sieved by the sieve with the particle size of 80-100 meshes, eluting in a manner that petroleum ether-ethyl acetate, or petroleum ether-acetone, or chloroform-acetone, or chloroform-ethyl acetate or the like, which are in the volume ratio of 85: (10-20), serve as a moving phase, and collecting fractions; and carrying out depressurized concentration on a fraction containing artemisinin, and crystallizing by using petroleum ether, thereby obtaining white needle-shaped artemisinin crystals. Compared with the prior art, the method has the advantages that the extraction and purification process for artemisinin is optimized, the solvent extraction operating steps and the types of used solvents are reduced, and the consumption of the solvents is reduced; and the obtained product has the advantages of stable quality, high yield, low cost and short consumed time.