Abstract: Two kinds of linseed oil were prepared through heat and cold pressing processes，and the volatile compounds from the prepared linseed oil were detected by means of the head space-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS)． Then，the contents of such volatile compounds as alcohols，aldehydes and ketones from the two kinds of linseed oil were discussed，and their content changes were also analyzed． Moreover，the odor activity value (OAV) was employed to determine the key aroma compounds in the two kinds of linseed oil． The results show that (1) the flavor compounds in both heat-pressed oil and cold-pressed one mainly include alcohols，aldehydes，ketones，furans，dimethyl sulfide，et al; (2) the flavor of the linseed oil can be attributed to the key aroma compounds，which are in the order of dimethyl sulfide ＞ hexanal ＞ propanal ＞2-butanol ＞ 1-hexanol ＞ 3-methyl-1-butanol ＞ 3-pentyl alcohol ＞ 2-methyl-propanol ＞ 2-methyl-1-butanol;(3) among these compounds，dimethyl sulfide and aldehydes make greater contribution to the overall flavor of the linseed oil，alcohols make a minor contribution to the overall flavor，but ketones and furans produce no actual effect on the overall flavor due to their greater threshold and smaller OAVs; and (4) the OAVs of dimethyl sulfide and aldehydes in the heat-pressed linseed oil are much greater than those in the cold-pressed samples，so the heat-pressed linseed oil has a stronger “grassy”smelling odor．

Key words: linseed oil, pressing process, key aroma compounds, odor activity value, head space-solid phase microextraction, gas chromatography-mass spectrometry