A medicament for inhibiting platelet aggregation, comprising atractylenolide compound or its derivatives, wherein the said atractylenolide compound has the following structural formula shown in formula (I), wherein R1 represents H or C1-C10 linear or branched alkyl, R2 represents H or C1-C10 linear or branched alkyl, and R3 represents H or hydroxyl. Use of atractylenolide compound shown in formula (I) or its derivatives in the manufacture of a medicament for inhibiting platelet aggregation. The medicament for inhibiting platelet aggregation of the present application has good efficacy without toxic-and-side effect, lower tendency of tolerance, convenient to take and applicable for preventing or treating diseases caused by high platelet aggregation rate.