Eight　new　emodin　derivatives　that　contain　large　conjugative　system　have　been　synthesized　and　their　anticancer　activities　also　have　been　evaluated.　The　result　shows　that　large　conjugative　system　can　not　enhance　the　anticancer　activities　of　emodin　derivatives,　but　the　introduction　of　an　alkylating　center　can　make　emodin　derivative　effective　against　cancer　cell　lines.　Compound　12　has　the　highest　alkylating　ability,　but　its　anticancer　activity　is　not　remarkable,　which　indicates　that　there　is　not　a　direct　correlation　between　the　chemical　reactivity　of　the　alkylating　agent　and　the　toxic　effects.