Provided are a fructosylated mangiferin, a preparation method therefor and a use thereof, wherein the fructosylated mangiferin has a structural formula represented by the following formula (I), the method for preparing the fructosylated mangiferin includes adding a substance with fructosylating enzymatic activity to a transformed liquid containing mangiferin for biotransformation reaction, so as to convert the mangiferin into the fructosylated mangiferin, wherein the transformed liquid contains the mangiferin and a glycosyl donor; as well as a use of the fructosylated mangiferin in preparation of a medicament for treatment of tumor-related diseases.