Urban transportation emission is characterized by high proportion, rapid growth and reaching peak slowly, which is a major emission sector in cities. A comprehensive and in-depth analysis of urban transportation emission is of great importance for carbon emission reduction. Based on the carbon emission data of New York, London, Tokyo, Paris and other global megacities, a horizontal and vertical comparative study on urban transportation carbon emission levels, structure and evolution is carried out. Then, a research on transportation planning goals, strategies, objectives, and actions is conducted. We find that most global megacities focus on land use and transportation integration, transportation system optimization, improvement of low carbon transportation modes proportion, optimizing the environment of walking and cycling, promotion of new energy vehicles. Some cities also conducted a quantitative measure and assessment of the planning. This study can be a reference for Chinese cities’ transportation carbon emission reduction.