The invention discloses a marine microorganism derived sesterterpene Asperterpinol B derivative and a synthesis method as well as application of saccharidase. The marine microorganism derived sesterterpene Asperterpinol B derivative is an ester type derivative with a chemical formula shown as a structural formula I, an amide type derivative shown as a structural formula II, a five-membered ring dehydrated derivative shown as a structural formula III or an eight-membered ring dehydrated derivative shown as a structural formula IV, or pharmaceutically acceptable salts or stereoisomers thereof ora prodrug molecule thereof: the formula I, the formula II, the formula III and the formula IV are shown in the description, wherein R0 is X-substituted alkane, alkene, alkyne, cycloalkane or phenyl with the carbon atom number of 1 to 10, ; X is H, Cl, Br, F, I, CN, NO2, CF3, OH, OCH3, COOH or COOCH3; R1 and R2 are alkane, alkene, alkyne, cycloalkane, N/O/S heterocycle or phenyl with the carbon atom number of 1 to 10; X is H, Cl, Br, F, I, CN, NO2, CF3, OH, OCH3, COOH or COOCH3. According to the marine microorganism derived sesterterpene Asperterpinol B derivative provided by the invention, anAsperterpinol B structure is modified to obtain a series of compounds with very good alpha-glucosidase activity and a new candidate drug molecule is provided for clinical treatment of diabetes mellitus.