The volatile compounds were extracted in the different parts of Melilotus indica (Linn.) All. by microwave-assisted headspace solid-phase micro-extraction(MAE-HS-SPME). Their constituents were analyzed and identified by gas chromatography-mass spectrometry combined with Kovats retention index. The results showed that 43 volatile constituents in the stem, 44 in the leaf and 71 in the flower of Melilotus indica (Linn.) All. were separated and identified. Accounting for 89.92 %、83.12% and 90.77% of the total peak areas, respectively. Which is the main component in stem 3,4-dihydrocoumarin (5.97%),dihydrocoumarin (55.29%) and Hexadecanal (4.44%). And in the leaves 3,4-dihydrocoumarin (11.84%) and dihydrocoumarin (48.15%). And in the flowers 3,4-dihydrocoumarin (6.08%),dihydrocoumarin (27.44%),p-isopropylanisole (6.20%) and thymol (5.19%). It was also observed that there were significant differences in the relative contents of three parts.