China has been the second CO2 emitter in the world, while the transportation sector accounts for a major share of CO2 emissions. Analysis of transportation sector CO2 emissions is help to decrease CO2 emissions. Thus the purpose of this paper is to investigate the potential factors influencing the change of transport sector CO2 emissions in China. First, the transport sector CO2 emissions over the period 1985-2009 is calculated based on the presented method. Then the presented LMDI (logarithmic mean Divisia index) method is used to find the nature of the factors those influence the changes in transport sector CO2 emissions. We find that: (1) Transport sector CO2 emissions has increased from 79.67 Mt in 1985 to 887.34 Mt in 2009, following an annual growth rate of 10.56%. Highways transport is the biggest CO2 emitter. (2) The per capita economic activity effect and transportation modal shifting effect are found to be primarily responsible for driving transport sector CO2 emissions growth over the study period. (3) The transportation intensity effect and transportation services share effect are found to be the main drivers of the reduction of CO2 emissions in China. However, the emission coefficient effect plays a very minor role over the study period. (C) 2011 Elsevier Ltd. All rights reserved.