Abstract: The essential oil of branch at night from Cestrum nocturnum Linn was analyzed and determined by GC/MS. 49 compounds were obtained and identified in the oil . The main constituents were 1-Heneicosyl formate(11.28％); Docosane(9.70％); 2-mono-Linolein(7.89％); Dibutyl phthalate; 10-Heneicosene(c,f); 1,3-dimethy Benzene; 1,2,3-trimethyl Benzene ; 4-ethyl-1,2-dimethyl Benzene; Tetracosane; 2,4-bis(1,1-dimethylethyl)-Phenol ; 1-ethyl-3-methyl Benzene, etc. Their toral content was 80.98％ of the identified volatile compounds.

Key words: Centrum nocturnum , Linn , Essential oil , GC-MSD