Abstract: The effects of aqueous ozone treatment on volatile organic compounds of grass carp fillets were systematically investigated. The volatile organic compounds (VOCs) changes of grass carp fillets with 0, 5, and 10 d at 4℃ storage were assessed using E-nose and headspace solid-phase microextraction (HS-SPME) GC-MS analysis. Principal component analysis (PCA) and detection frequency analysis (DFA) showed differences in the VOCs between processing group and control sample during refrigerated storage. 43 volatile components were identified by SPME/GC-MS. Fishy odor VOCs, such as hexanal, pentanal, 1-octene-3-ol, 2, 3-octanedione and ethyl lactate, were detected in the fresh sample, while those VOCs reduced in the processing group with the extension of ozone treatment time.The composition of VOCs in all samples significantly changed during storage. The relative content of unpleasant VOCs, methyl thioacetate, indole, amines and so on, in treatment group was lower than that of the control sample. This study indicated that aqueous ozone treatment, possibly a promising strategy could reduce the unpleasant odor emission from fresh grass carp and delay the generation of off-flavor in the grass carp fillets during storage.