Headspace solid-phase microextraction(HS-SPME) was used to isolate the off-flavor volatile compounds, which are formed during the oxidation of porcine liver and unsaturated fatty acids in porcine liver induced by iron. Three fibers for HS-SPME method development were tested, and the polydimethylsiloxane/divinylbenzene(PDMS/DVB) fiber was selected as providing the best detection of analyzed compounds. In the oxidized arachidonic acid, the major compounds identified were hexanal, 1-octen-3-one(metallic), (Z)-4-heptenal, (E)-2-octenal, 1-octen-3-ol(mushroom), (Z)-2-nonenal (cardboard-like), and (E,E)-2,4-decadienal(fatty, oily). In the oxidized linolenic acid, the major ones were (E,E)-2,4-heptadienal(fishy), (E,E)-3,5-octadien-2-one and (E,Z)-2,6-nonadienal. Moreover, those of th oxidized porcine liver with iron were hexanal, 1-octen-3-one, (Z)-4-heptenal, (E,Z)-2,4-decadienal and (E,E)-2,4-decadienal. These results showed that the fishy and metallic off-flavor in porcine liver were due to the oxidation of unsaturated fatty acids in porcine liver.