Abstract: Four varieties of Gannan navel oranges(Newhall,Bonanza,Washington,Navelina)were used as raw materials,the maturity of the fruits was determined by detecting the soluble sugar,titratable acid,soluble solids content and solid-acid ratio,the essential oils were extracted by steam distillation from peels,and the volatile components were studied by gas chromatography-mass spectrometry(GC-MS). The differences in yield,volatile chemical composition and content were compared. Results showed that the solid-acid ratios of the four varieties of navel oranges were all greater than or equal to 20.0,indicated that the fruits were in a mature state. The yields of essential oil from four varieties of Gannan navel orange peels were as followed:Newhall(1.05%)＞Navelina(0.94%)＞Washington(0.91%)＞Bonanza(0.75%). 21 volatile components were identified from four samples,including 13 olefins,3 alcohols and 5 aldehydes,with predominantly olefinic compounds. Besides,eleven kinds of volatile components were identified in the peel of Newhall navel orange,d-limonene(92.962%),myrcene(2.851%)and ocimene(1.039%)were the main aroma components;13 kinds of volatile components were identified in Bonanza,d-limonene(92.328%),myrcene(2.700%),and 3-methylene-6-(1-methylethyl)cyclohexene(1.020%)were main aroma components;Fourteen kinds of volatile components were identified in Washington,d-limonene(92.322%)and β-pinene(2.653%)were the main aroma components;Eleven kinds of volatile components were identified in Navelina,myrcene(47.036%),2-decene(15.313%),3-methylene-6-(1-methylethyl)cyclohexene(11.593%)were main aroma components. The results of this study provided references for the development and utilization of essential oils from Gannan navel oranges.