A gas chromatography and mass spectrometric(GC-MS) method was developed for the determination of in vivo metabolism of chlorpromazine, and its mass chromatograms were analyzed.Five female Wistar rats were gavaged with chlorpromazine hydrochloride and the 24-hr urine sample after administration were collected.The sample was hydrolyzed,and extracted by solid phase extraction(SPE).The metabolites were analyzed by GC-MS under EI and PCI mode.The mass chromatograms of the parent drug，blank urine and the sample were compared and identified.Sixteen compounds such as phenothiazine，2-chlorophenothiazine，N-(2-propenyl)-2-chlorophenothiazine，promazine，2-hydroxylphenothiazine，demethylchlorpromazine，3-hydroxylpromazine，promazine sulfoxide，2-chloro-7-hydroxylphenothiazine，chlorophenothiazine sulfone，7-hydroxylchlorpromazine，chlorpromazine sulfoxide，dihydroxylchlorpromazine，desmethylchlorpromazine sulfoxide，N-acetyl-demethylchlorpromazine，N-acetyl dedimethylchlorpromazine were identified as metabolites, in which 2-chlorophenothiazine，promazine，demethylchlorpromazine，7-hydroxylchlorpromazine and chlorpromazine sulfoxide were the main metabolites.The results suggested that at least three metabolic pathways for chlorpromazine, including oxidation，demethylation and dehalogenation, are operative in rats.