The present invention provides a thienopyrimidinone derivative, a preparation method thereof, and an application thereof in manufacturing of antitumor drugs. The derivative has a structure as represented by general formula (I), comprising a single stereoisomer or racemic mixture thereof, wherein R is independently selected from hydrogen (H) or deuterium (D)； R1 and R2 independently, at each occurrence, represent H, D, F, Cl, I, cyano group (CN), or N3, and when R represents H, R1 and R2 do not synchronously represent H； R3, R4 and R5 independently, at each occurrence, represent an alkyl group, a cycloalkyl group, a heterocyclic group, an aromatic ring group, or a heteroaryl ring group, which are substituted or unsubstituted.
