Taking the balanced panel data of 60 countries from 1971 to 2012 years as a sample, the relationship between urbanization and greenhouse gas (GHG) emissions was checked based on the threshold model. It was found that the relationship between the urbanization ratio and GHG emissions was always positive, suggesting that urbanization will inevitably lead to an increase in GHG emissions, irrespective of how high the rate of urbanization is. However, when the urbanization ratio passed 23.59% or the GHG emissions exceed 42,287 kt of CO2 equivalent, urbanization will have more impact on GHG. Also, the urbanization paths influence the relationship between urbanization and GHG emissions. When the population in urban agglomerations of more than 1 million of total population is higher than 20.01% or the population in the largest city of urban population is above 48.27%, positive correlation between urbanization and environmental pollution will be more significant