Abstract: The Fatty acids in the oil of three freshwater fishes, namely tilapia, grass carp and silver carp were exacted by V(chloroform):V(methanol)＝2:1, derivatived by BF3-methanol and evaluated by gas chromatography-mass spectrometry. The results show that saturated, monounsaturated and polyunsaturated fatty acids are present at 4.98-12.63, 7.50-11.22 and 8.0-12.02 g kg^－1, respectively. The n-6/n-3 of polyunsaturated fatty acids are 1.16-2.46. It indicates that the oil of freshwater fishes is benefic to health and should be exploited.