The present invention belongs to the technical field of organic chemistry, and specifically relates to a method for preparing rosuvastatin sodium. The method of the invention comprises: reducing 4-p-fluorophenyl-6-isopropyl-2-(N-methyl-methylsulfonylamino)pyrimidine-5-carboxylic acid (VII) in the presence of a borohydride, an alkyl-substituted chlorosilane and an assistance in an organic solvent to prepare 4-p-fluorophenyl-5-hydroxymethyl-6-isopropyl-2-(N-methyl-methylsulfonylamino) pyrimidine (VIII); then performing a reaction of the compound VIII with a triphenyl phosphonium salt in an organic solvent to prepare a ((4-p-fluorophenyl-6-isopropyl-2-(N-methyl-methylsulfonylamino)-5-pyridyl)-methyl)triphenyl phosphonium salt (IX); performing a stereoselective Michael addition reaction of (S)-trans-4,5-dihydroxy-pent-2-olefine acid ester (II) with furfural (III) to prepare a 2-((4R,6S)-2-(furan-2-yl)-6-hydroxymethyl-1,3-dioxane-4-yl)acetate (IV); oxidizing the compound IV to prepare a 2-((4R,6S)-2-(furan-2-yl)-6-formacyl-1,3-dioxane-4-yl)acetate (V); performing an olefination reaction of the compound V with the (4-p-fluorophenyl-6-isopropyl-2-(N-methyl-methylsulfonylamino)pyrimid-5-yl)-methyl triphenyl substituted phosphonium salt (IX) or phosphate to prepare 2-((4R,6S)-6-(trans-2-(4-p-fluorophenyl-6-isopropyl-2-(N-methyl-methylsulfonylamino)pyrimid-5-yl)vinyl)-2-(furan-2-yl)-1,3-dioxane-4-yl)acetate (VI); and performing deprotection and sodium salt formation of compound VI to prepare rosuvastatin sodium (I). The method has easily obtainable raw materials, and is simple to operate and suitable for industrial productions.