According to the calculation method of the IPCC, the paper calculates the composition and intensity of carbon emissions from transportation energy consumption in China from 2000 to 2011. Based on logarithmic mean divisia index (LMDI) decomposition technique, changes of carbon emissions quantity are analyzed by three factors which are the transportation energy intensity, the economic growth and the transportation energy structure. The results show: (1) Transportation energy intensity was significantly decreased. Under its influence carbon emission intensity from the transportation energy was decreased, indicating that the energy efficiency was improved continuously. (2) Transport carbon emissions were in a growing trend. The greatest influence factor was the economic growth which had a positive effect and enlarged transportation carbon emissions quantity. On the other hand, the factors of the transportation energy intensity had a negative effect. Except 2011, the transportation energy structure always had a negative effect, which reduced transportation carbon emissions quantity.