OBJECTIVE: To study the chemical constituents of the chloroform from Hedyotis diffusa. METHODS: Silica gel, Sephadex LH-20 column chromatography and preparative thin layer chromatography were conducted to classify and purify of chemical constituents of the chloroform from H. diffusa, the chemical structures were analyzed and identified based on physicochemical properties and spectral data. RESULTS: Totally 11 compounds were obtained from the chloroform of H. diffusa, namely 2-hydro- xy-3-methylanthraquinone (1), 2-hydroxy-1-methyl-3-methoxyanthraquinone (2), 2-hydroxy-1-methoxyanthraquinone (3), dibutyl phthalate (4), rubiadin(5), ursolic acid (6), hedyotiscone B (7), scopoletin (8), 2, 6-dihydroxy-3-methyl-4-methoxyanthraquinone (9), 2-hydroxy-3-hydroxymethylanthraquinone (10) and n-hexadecane (11). CONCLUSIONS: Compound 4, 7, 10, 11 are firstly obtained from H. diffusa, the study had laid certain foundation for the quality evaluation of H. diffusa.