Abstract: In this experiment, pear (Pyrus bretschneideri Rehd C.V.changba) fruits stored at 0℃ for six months after treatment with 250 nL/L 1-MCP(1-methylcyclopropene) and non-treated fruits stored in the same conditions were used as materials to study the effects of different film packaging thickness(0.03 mm, 0.06 mm and 0.09 mm, respectly) on the injury of carbon dioxide to pears during shelf life. The results showed that the higher concentration of CO₂ was the main factor to cause fruit core browning, and the CO₂ concentration in packaging bags with 0.03 mm in thickness was much lower than that in any other bag of packaging with 0.06 mm or 0.09 mm in thickness(P＜0.01). Packaging film with a thickness of 0.03 mm could maintain the total polyphenol content, and decrease decay and core browning index of fruits that both treated and non-treated with 1-MCP. No significant difference occurred in the flesh whiteness between treatments of three kinds of packaging thickness during shelf life(P＞0.05); 1-MCP treatment could decrease the decay index of fruit than that of CK. No significant effects on total polyphenol content, flesh whiteness and core browning index were observed in fruits treated with 1-MCP, however.