The present invention relates to an amino pyran ring derivative and a composition and use thereof, and in particular, to an amino pyran ring derivative represented by general formula (I) or a stereoisomer, a pharmaceutically acceptable salt or a prodrug thereof, a pharmaceutical composition comprising the derivative, and their medical use in the manufacture of a di-peptidyl peptidase IV (DPP-IV) inhibitor, in formula (I) the substituents are defined the same as those in the specification.