To investigate the antibacterial activity of camphor tree leaves’ polyphenol in food preservation, the effect of camphor tree leaves’ polyphenol was studied, on 7 strains of pathogenic bacteria and spoilage bacteria, and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined. Furthermore, the effect of camphor tree leaves’ polyphenol on the total colony, pH value, total volatile basic nitrogen (TVB-N) content and trimethylamine content of grass carp meat during cold storage was investigated. The camphor tree leaves’ polyphenol inhibited these strains effectively, the MIC on Pseudomonas fluorescens, Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Penicillium citrinum, Aspergillus niger, Mucor mucedo were 0.500, 0.625, 1.250, 1.250, 2.500, 2.500 mg/mL, respectively, and the MBC were 1.000, 1.250, 2.500, 2.500, 2.500, 2.500, 2.500 mg/mL, respectively. The camphor tree leaves’ polyphenol can significantly inhibit the growth of microorganisms in the fish, and the pH value, TVB-N content, and trimethylamine content increased slower than that of the control, the shelf life of refrigerated fish increased from 3 days to 6 days, 8 days for 5, 10 mg/g treatment, respectively. The camphor tree leaves’ polyphenol could be used as effective natural antibacterial agent in fish meat preservation.