E-commerce industry is escalating at an unprecedented pace, which has led to the rapid growth of online shopping and the prosperity of express delivery service. However, there is increasing concern on the waste of the large amount of packaging materials from the express delivery sector, which has not been well documented in China, as well as many other countries. This paper employs the life cycle assessment method to quantify the implicit environmental impacts (measured by carbon dioxide equivalents, CO(2)e) of packaging materials’ raw material production (embodied impact), boxes/bags manufacturing, and end-of-life stages, and then evaluates their reduction potentials. The results indicate that the waste of express delivery packaging materials has surged from 0.2 million metric tons (Mt) in 2007 to 9.2 +/- 5% Mt in 2018 in China. Consequently, the total CO(2)e from packaging materials’ overall life has soared from 0.3 Mt in 2007 to 13.2 +/- 5% Mt in 2018. Raw materials’ embodied impact, manufacturing process, and end-of-life phases account for 68.4%, 18.8%, and 12.7%, respectively. Our scenario-based analysis implies there are great opportunities to reduce packaging materials consumed and then mitigate their impact. These preliminary findings could not only help to better understand the impact of packaging materials for the express delivery sector but also inform evidence-based policymaking of green development in China’s express delivery industry and beyond. (c) 2020 Elsevier Ltd. All rights reserved.