Vibriospp. cause vibriosis in many saltwater and freshwater aquatic species, such as fish, crustaceans, and mollusks.Vibrio parahaemolyticusandVibrio alginolyticusare among the fewVibriospecies commonly found in infections in fish. This study aimed at investigating the chemical composition and evaluating the antibacterial activities ofSalix babylonicaL. The ethyl acetate (LL2) and methanolic (LL3) extracts were used to evaluate the resistance of strains asV. parahaemolyticusLBT6 and VTCC 12233, and two strains ofV. alginolyticus, NG20 and ATCC 17749, and compared their efficacy with cefotaxime in order to find an alternative to antibiotics in the treatment of vibriosis. The obtained results show that the LL2 extract, with its major components identified as chrysoeriol, luteolin, and β-sitosterol, exhibited a bacteriostatic effect against all the tested strains. In parallel, the LL3 extract, with the four major compounds luteolin-7-O-β-D-glucopyranoside, salicin, p-hydroxy benzoic acid, and β-sitosterol-3-O-β-D-glucopyranoside, showed significant bactericidal activity against these four strains; the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) varied from 2.0 to 3.0 μg/mL and from 3.5 to 5.0 μg/mL, respectively. Moreover, the LL3 extract could effectively increase the survival rate of the challenged fish at a dose of 5% (w/w) for the zebrafish (Danio rerio) and 3% (w/w) for the sea bass (Lates calcarifer). The LL3 extract showed a potential application ofS. babylonicaL. in the prevention and treatment of vibriosis in fish.