OBJECTIVE To separate and identify the chemical constituents of the whole plant of chinese herb -Melastoma Dodecandrum- Lour.METHOD S The flavonoid constituents were isolated by solvent extraction and chromatography.Their chemical structures were identified on the basis of physicchemical constant and spectral data.RESULTS Seven compounds were isolated and identified as luteolin (Ⅰ),luteolin-7-O-β-glucoside (Ⅱ),luteolin-7-O-β-galactoside (Ⅲ),quercetin (Ⅳ),quercetin-3-O-β-glucoside (Ⅴ),quercetin-3-O-β-galactoside (Ⅵ) and avicularin (Ⅶ).CONCLUSION The abovementioned compounds were separated from the plant for the first time.