Liquid-assisted Wittig reaction is used to synthesis of Rosuvastatin intermediates (1,3-Dioxane-4-acetic acid, (4R,6S)-6-[(1E)-2-[4-(4-fluorophenyl)-6- (1-methylethyl)-2-[methyl(methylsulfonyl)amino]-5-pyrimidinyl]ethenyl]-2,2-dimethyl-1,1-dimethylethyl ester). Evaluate the reaction using common green chemistry metrics: environmental factor (E-factor), and systematic investigation of the reaction has been made in order to study the various factors affecting the reaction. The E-factor of Liquid-assisted Wittig reaction is about a quarter of the traditional method. Under optimal conditions, the conversion rate can reach 99.2 and the E:Z ratio can reach 76:24.