Objective To investigate the antibacterial effect of ε-polysine hydrochloride on Shewanella baltica and Pseudomonas fluorescens derived from large yellow croaker.Methods The antibacterial effects of ε-polylysine hydrochloride on the growth of Shewanella baltica and Pseudomonas fluorescens was analyzed by the minimum inhibitory concentration and the growth curve. By measuring the bacterial fluid conductivity, alkaline phosphatase activity, ultraviolet absorbent substances and biofilm formation inhibition rate, the cell integrity and permeability were evaluated. The aerobic plate count and total volatile basic nitrogen of the flesh of large yellow croaker inoculated with spoilage bacteria were determined the effect of ε-polylysine hydrochloride on the spoilage ability of Shewanella baltica and Pseudomonas fluorescens.Results The minimum inhibitory concentrations of ε-polylysine hydrochloride against Shewanella baltica was 0.250 mg/mL, while Pseudomonas fluorescein was 0.125 mg/mL. With the treatment of ε-polylysine hydrochloride, the growth of Shewanella baltica and Pseudomonas fluorescein was significantly inhibited, and the conductivity, AKP enzyme activity and UV absorbent leakage were significantly increased in a mass concentration dependent manner. Fish inoculated with Shewanella baltica and Pseudomonas fluorescein showed a significant decrease in total bacterial count and TVB-N values.Conclusion ε-polylysine hydrochloride can destroy the cell integrity of Shewanella baltica and Pseudomonas fluorescein, inhibit the growth and affect the spoilage ability.