The effects of active modified atmosphere packaging (MAP) on the postharvest quality of shiitake mushrooms stored at cold temperature (4°C) were investigated. The gas components were 2% O2+7% CO2 (MAP1), 2% O2+10% CO2 (MAP2) and 2% O2+13% CO2 (MAP3), respectively. The results showed that active MAP could extend the shelf-life of shiitake mushrooms to 17 d and the concentration of carbon dioxide could influence the postharvest quality of shiitake mushrooms. MAP2 treatment inhibited the increase in respiration rate and malondinaldehyde (MDA) contents, delayed the decrease in firmness, soluble sugar and vitamin C, and obviously reduced the activity of polyphenol oxidase (PPO) and the degree of browning, therefore maintaining better quality.