OBJECTIVE：To clarify the bio-transformation form of apigenin in rats，and to speculate its possible metabolic pathway. METHODS：Rats were divided into blank group and medication group（apigenin 200 mg/kg，i.g.）with 6 rats in each group. Urine and feces samples were collected from 2 groups within 24 h after medication. After corresponding treatment，urine and feces samples were analyzed and detected by HPLC-IT-TOF-MSn under cation mode and anion mode. RESULTS：9 metabolites were identified in urine sample of rats from medication group，i.e. 2，3-double bond reduction of apigenin（U1，U7，U8，U9），bonded to glucuronic acid（U2，U3，U4），bonded to sulphate（U5，U6，U7，U8，U9）and bonded to glucose（U2）. 4 metabolites were identified in feces sample of rats from medication group，i.e. 2，3-double bond reduction of apigenin（F3），bonded to glucuronic acid （F2）and bonded to glucose（F1）. CONCLUSIONS：Apigenin mainly exists in form of prototype drug in rats. The reduction happens on 2，3-double bond by the intestinal bacteria，and the product of apigenin boned to glucuronic acid or glucose can be formed when excreting in intestinal tract and rats in vivo，while the product of apigenin boned to sulphate can be formed only when excreting in rats in vivo.