PURPOSE: A cosmetic composition containing Sodium Danshensu for skin whitening is provided to suppress tyrosinase activity and melanogenesis. CONSTITUTION: A cosmetic composition for skin whitening contains a compound of chemical formula 1 as an active ingredient. The compound of chemical formula 1 is isolated form Sodium Danshensu extract. The content of the compound is 0.001-30.0 weight%. A method for preparing the compound comprises: a step of purifying and drying Sodium Danshensu, pulverizing uniformly; a step of a step of isolating extract using organic solvent; and a step of performing chromatography.본 발명은 단삼소납을 함유하는 피부미백 화장료 조성물에 관한 것으로서, 더욱 상세하게는 단삼(丹參, Salviamiltiorrhiza Bunge) 추출물로부터 분리된 단삼소납(Sodium Danshensu)이 티로시나제 활성 저해, 멜라닌 생성 저해 등의 피부 미백 활성에 우수함을 확인함으로써, 단삼소납을 유효성분으로 함유하는 피부 미백 화장료 조성물에 관한 것이다.