The synthetic process for Rivaroxaban♂ was improved.4-(4-aminophenyl)-3-morpholinone♂was used as the starting material and reacted with R-epichlorohydrin♂ followed by addition, cyclization reaction with N, N'-carbonyldiimidazole;substitution with potassium phthalimide♂;then hydrolyzed in hydrazine hydrate, and finally with 5-chlorothiophene-2-carboxylic acid chloride♂. The final product of rivaroxaban was prepared by acylation reaction with a total yield of 46.1%. A purity of more than 99.8% with the maximum single impurity of less than 0.1% was obtained. In order to control the quality of ♂ and establish the quality standard of ♂ API, the e.e value of the product was increased to more than 99% according to this improved synthetic process while the enantiomeric impurity(related substance A) was prepared The enantiomeric impurity was also confirmed by MS and NMR.