Abstract: Modelling modified atmosphere packaging (MAP) with perforated film is one of key to design the MAP system of fruits and vegetables. Based on the relationship of the aperture and molecular mean free path, and combined with the respiration rate model of produce, a mathematical model based on Fick’s law for predicting O2 and CO2 exchanges in MAP with micro perforated films was developed. The respiration rates of Lentinula edodes were estimated using the closed system method, and the respiration model for Lentinula edodes was established based on the Michaelis-Menten equation. Fresh Lentinula edodes were packed in plastic jars filled with air and modified atmosphere, which sealed by polyethylene films with different perforation number and perforation diameters. All samples were stored under 25℃ and a relative humidity of 50% for more than 50 hours, measuring the gas composition within packs during the storage. Comparison between model prediction and experimental data for gas composition within packs was conducted. Results indicated the model predictions agree well with the experimental data.