Abstract: Both single factor and orthogonal experiments were used to optimize conditions for purification of linoleic acid from Carya cathayensis Sarg. oil by urea adduction fractionation. Effects of adduction temperature， time， the ratio of fatty acid and urea and the ratio of methanol and urea on the purity and yield of linoleic acid were investigated. The results showed that the optimal purification conditions were the ratio of fatty acid and urea （m/m） at 0.3， the ratio of methanol and urea （V/m） at 2.5， adduction temperature at -5℃， and adduction time of 24 h, in which content of linoleic acid in Carya cathayensis Sarg. oil increased from 23.80% to 80.73%.

Key words: Carya cathayensis Sarg. oil, urea adduction fractionation, linoleic acid