Abstract:Isolation and identification of cis-5, 9-octadecadienoic acid, cis-5, 9, 1200 tadecatrienoic acid, and cis-5, 11, 14-eicosatrienoic acid from seed-oil of Pinus tabulaeformis Carr. and also the regularity of distribution of the three fatty acids in 12 kinds of seed-oils from plants of Pinaceae indigenous to northeast of china were reported.