In order to study the effect of dietary replacement of fish oil by vegetable oil on the taste quality of Chinese mitten crab, vegetable oil[W(soybean oil):W(rapeseed oil)=3:1] was used to replace different levels of fish oil (0%, 50% and 100%) to make three kinds of feeds with equal nitrogen and fat (F1, F2 and F3, with F1 as control) to feed adult female crabs (mass 95±10 g) for 70 days. The proximate composition, the contents of free amino acids and taste nucleotide of the edible parts of the three groups of crabs, and the overall taste difference by electronic tongue were analyzed in combination with sensory evaluation. The results showed that the crude lipid content of meat, gonads and hepatopancreas of three groups of crabs had no significant difference. The crude protein content of hepatopancreas of F2 was significantly higher than that of F1 and F3, while the crude protein content of meat of F3 was significantly lower than that of F1 and F2. Compared with F1, the umami and sweet sensory intensity value as well as the total amount of taste nucleotides and equivalent umami concentration in the edible part of F2 were increased, whereas those of F3 were decreased. Moreover, the content of umami and sweet amino acids of gonads and hepatopancreas of F2 were also increased. The above results showed that replacement of fish oil by 50% vegetable oil in feed not only improved the nutritional quality of Chinese mitten crab, but also enhanced its taste quality, which provided a reference for the improvement of the taste quality of cultured Chinese mitten crabs and the development of fish oil substitute sources in fattening feed.