Pleurotus nebrodensis were packaged with PVC and PE with different thickness (0.03 mm and 0.05 mm) at 4°С. Package gas composition, respiration rate and relative electrolyte leakage were measured during storage at 4°С and 95%RH for 28 days. The results showed that auto modified atmosphere pattern would be formed at 7th day of the storage. The atmosphere concentration in the package of 0.05 mm films was 0.1~5% O2 and 6%~10%CO2 after 7days, then maintaining the atmosphere concentration stable in the following days of the storage test. Compared to the 0.03 mm film, the 0.05 mm film was more effective for decreasing respiration rate and electrolyte leakage of pleurotus nebrodensis to delay its senescence. It could be taken for granted that pleurotus nebrodensis was apt to storage in the circumstance of low O2 and high CO2.