To improve the accuracy and achieve a good level of detail, a process-based method was adopted in this paper to conduct a life-cycle CO2 emission analysis of China's construction sector from 2005 to 2012 by quantifying the CO2 emission during the six life-cycle stages, including building materials manufacturing, building materials transportation, building construction, building operation, building demolition as well as construction and demolition (C&D) waste disposal. The results indicate that the CO2 emission of China's construction sector rose moderately from 2005, and has increased considerably since 2010. The total CO2 emission mainly stems from building materials manufacturing stage (73%) and building operation stage (24%). The CO2 emission from steel and cement account for the most of the CO2 emission at building materials manufacturing stage (87%). The CO2 emission of road transportation with 83% shares the highest proportion at building materials transportation stage. The CO2 emission of centralized heating with 49% is the dominant source of CO2 emission during building operation stage. The CO2 emission at construction and demolition (C&D) waste disposal stage is mainly generated from demolition waste with 86%. These findings could provide references for measures to take targeted at various life cycle stages. (C) 2015 Elsevier B.V. All rights reserved.