The bacteriostatic activity and bacteriostatic mechanism of thymol to Listeria monocytogenes were studied and the thymol-chitosan composite membrane was prepared to study the properties of the composite membrane and its preservation effect on pork. The results showed that the minimum inhibitory concentration of thymol on Listeria monocytogenes was 12.5 μg/mL. The experimental study of conductivity, nucleic acid and protein leakage found that thymol caused by mononuclear proliferative Leptospira cell membrane damage, so that bacterial cell inclusions caused by bacterial death. With the increase of thymol concentration (0.25%, 0.50%, 1.00%) in the thymol-chitosan composite membrane, the hardness and puncture strength of the membrane gradually decreased. The temperature and thymol concentration affected the removal of DPPH free radicals by composite membranes. At 25 ℃, the scavenging rate of 1.00% thymol-composite membrane was the highest at 25 ℃; the growth and reproduction of microbes in pork were reduced by the thymol-chitosan composite membrane, the total number of colonies decreased and the chilling period of pork was prolonged.