The invention relates to the field of pharmaceutical chemistry, and particularly relates to a compound represented by formula (I), a preparation method thereof, and a medical use thereof. In the compound represented by formula (I), a lactulose group is linked to a heteroatom in an aglycone (G) through a glycosidic bond. The aglycone (G) is a group formed by removing a hydrogen atom from heteroatoms of an active drug molecule, and the lactulose group is linked to the heteroatom in the aglycone (G) through an α-glycosidic bond or a β-glycosidic bond. Drug metabolism tests proved that the lactulose glycoside compound according to the invention can pass through a mammalian gastrointestinal tract without being significantly absorbed by the gastrointestinal tract and without being significantly hydrolyzed by the endogenous enzyme of the mammalian host, such that the lactulose glycoside compound can reach a colonic region of the mammal, and the active drug can be released in the colon under the action of the colonic flora. The lactulose glycoside compound has effects of colon targeted drug delivery and can be used in the prevention or treatment of intestinal diseases.
