The work aims to study the impact of different heat treatment on the barrier property of PLA films. The food stimulants wrapped with PLA and PE films were under heat treatment. The change in oxygen permeation, water absorption capacity and moisture permeability of PLA and PE films after heat treatment were analyzed. The oxygen permeation of PLA and PE films without heat treatment was 3737.27 and 1469.54 cm3/(m2•d•Pa), respectively. No data could be detected by the air permeability tester due to the defects occurring in PLA and PE films after heat treatment. The moisture permeability of PLA film was 80~124 g•cm/(cm2•s•Pa), and the moisture permeability of PE film was 4.9~29.6 g•cm/(cm2•s•Pa). During steaming and heating, if the storage time was three weeks, the tensile strength, moisture permeability and water absorption rate of PLA would decrease. The traditional steaming and heating for disinfection has the greatest effect on the barrier property of PLA. Such operation is not applicable to the food packaging materials to be steamed for disinfection. For the prediction of food’s shelf life, the impact of the disinfection way on the properties of packaging materials should not be neglected.