Effect of flavor improvement on the largemouth bass fermented moderately by Lactobacillus plantarum, yeast and the compound bacteria was analyzed. Sensory analysis, electronic nose and monolithic material sorptive extraction combined with gas chromatography-mass spectrometry (MMSE-GC-MS) were used to detect the volatile flavor compounds of the bass after different microorganisms’ fermentation, while the changes of flavor compounds were analyzed before and after deodorization. The results of sensory evaluation and electronic nose analysis showed that there were distinctive differences in odor between different treated groups and the control. The results of GC-MS showed the contents of octanal, nonanal, decanal, 1-Penten-3-ol, 6-Methyl-5-heptane-2-one and other fishy odors were decreased to different degrees, due to being converted and utilized by microorganisms, indicating that the microbial fermentation had the effect on removing fishy odors. Among them, 2,3-pentanedione, geranylacetone and other volatile flavor compounds with pleasant odors such as creamy and floral aroma were produced in Lactobacillus plantarum treated group, which showed better coordinated flavors and effect of removing fishy odors combined with aroma enhancement.