The work aims to study the effect of gas permeability and permselectivity of films on the AMAP packaging of strawberry. The respiratory rate of the strawberry was measured in the closed system method. In combination with the Michaelis-Menten equation, the relationship between the respiratory rate and the packaging film permeability was derived. When the dynamic balance was reached in the actual storage, the respiratory rate of the strawberry was measured by combining the film with the known permeability and the permeable system method. The gas selection ratio suitable for the AMAP material of the strawberry was derived according to the Michaelis-Menten and dynamic balance equations. Based on that, the PLLA was modified by the PEG with the strong selective solubility for CO2, so as to adjust its permeability and CO2/O2 permselectivity. The atmosphere composition in the PLGL35G20 film package modified by PEG could reach a fairly ideal AMAP concentration of the strawberry under a certain usable area. PEG has properly adjusted the PLLA film’s modified atmosphere packaging performance. It is predicted that the gas permeability and selectivity of the film can be adjusted by adjusting the length of PEG and PLLA blocks and the content of PEG in the copolymer film. Finally, the film can meet the best requirements of the AMAP packaging for different fruits.