Objective To determine the constitution and content range of characteristic fatty acids in common vegetable oils,and to discuss how to utilize these indicators to identify the quality of vegetable oil.Methods One hundred and twenty five common vegetable oil samples of 9 kinds(two batches for each kind) were collected from six cities.The constituents of 46 fatty acids and characteristic fatty acids of vegetable oils were identified according to GB/T 22223—2008.Results The characteristic fatty acids in rapeseed oil,tea oil,flaxseed oil,sunflower oil and rice oil were erucic acid,oleic acid,α-linolenic acid,linoleic acid and palmitic acid,respectively;the characteristic fatty acids in peanut oil were C20∶0,C24∶0 and C22∶0 fatty acids.The ratio of n6/n3 in soybean oil was the most closed to the value recommended by the Chinese nutrition association.The total content of oleic acid and linoleic acid and the characteristic composition of palmitic acid and stearic acid were relatively stable in sesame oil,which could be used for identification.The characteristic fatty acid in corn oil was not obvious.Conclusion Combination of characteristic fatty acid monomer,fatty acid composition,as well as n6/n3 ratio analysis,the purpose of qualitative detection of common vegetable oils could be achieved.