Disclosed is a method for preparing 2'-deoxy-2',2'-difluorocytidine of Formula I comprising, preparing an optically pure 3R-hydroxypropane amide compound of Formula VIII from an optical ester compound of Formula IX using an optically active chiral amine, preparing an optically pure D-erythro-2,2-difluoro-2-deoxy-1-oxoribose compound of Formula V from the compound of Formula VIII, glycosylating the compound of Formula V with a nucleobase to prepare the 2'-deoxy-2',2'-difluorocytidine of Formula I as a .beta.-nucleoside. With the present invention, it is possible to prepare an optically pure compound of Formula I in a high purity and a high yield. In the Formulae, R.sub.1 and R.sub.2 are protecting groups and are each independently benzoyl, 4-methylbenzoyl, 3-methylbenzoyl, 4-cyanobenzoyl, 3-cyanobenzoyl, 4-propylbenzoyl, 2-ethoxybenzoyl, 4-t-butylbenzoyl, 1-naphthoyl or 2-naphthoyl, R.sub.3, R.sub.4 and R.sub.7 are each independently C.sub.1-C.sub.3 alkyl, R.sub.5 is methyl or ethyl, R.sub.6 is hydrogen, methyl or methoxy.