Abstract: This paper aimed to investigate the antibacterial properties of Quercus mongolica shell extract (QMSE) and its application effect in fresh pork preservation. Initially, QMSE was prepared with 20%, 40%, and 60% concentrations of ethanol to assess its antibacterial properties and the correlation with the active ingredient. Subsequently, an orthogonal experiment was conducted to optimize the additive amounts of each component in the preservative, and the preservation effects on fresh pork stored at 4 °C for 8 days were analyzed. Results showed that, QMSE prepared with 40% ethanol exhibited the most potent antimicrobial effect, showing the highest inhibitory activity against Escherichia coli with an inhibitory diameter of (11.58±0.75) mm, followed by Staphylococcus aureus and Salmonella at (10.53±0.71) mm and (8.75±0.07) mm, respectively. Correlation analysis indicated that polyphenols played a crucial role in bacterial inhibition. The optimal formulation of the QMSE preservative comprised 6.0% QMSE, 3.0% sodium alginate, 2.0% octenyl succinic anhydride modified rice starch ester (OSA-RSE), 4.0% glycerol, 0.3% polyethylene glycol, and 84.7% distilled water. The inhibitory diameter of the QMSE preservative prepared under these conditions for the three indicator bacteria was Escherichia coli (11.99±0.03) mm, Salmonella (7.99±0.05) mm, and Staphylococcus aureus (10.70±0.05) mm, the tensile strength of the film was (3.61±0.05) MPa, the elongation at break was (34.87±0.30)%, and the water vapor transmission was (99.14±0.20) g/(m²·24 h). Preservation experiments confirmed that the QMSE preservative significantly inhibited the increase in total volatile base nitrogen (TVB-N) value, total colony count, pH, and the deterioration of sensory scores in fresh pork during storage (P<0.05). This study offers valuable insights into the potential application of QMSE as a natural bacteriostatic agent in food ingredient and product preservation.