Reducing the anthropogenic greenhouse gas emissions is the fundamental way to address climate change, which has been widely accepted by international community. Studying the trends of carbon emission intensity for each country’s economic activity could provide a scientific basis for predicting each country’s future tendency as well as formulating the reduction targets for carbon emission intensity. Based on the carbon dioxide emission data from Oak Ridge National Laboratory CO2Information Analysis Center (CDIAC)，GDP data from Statistics on World Population, GDP and Per Capita GDP，1-2008 AD，and the secondary industry value add share of GDP data from World Bank，we selected the seven industrialized countries （USA，UK，France，Germany，Japan，Italy，Canada）as well as the five emerging economies（China，India，Brazil，Mexico，South Africa）as the analysis objects to compare the trends of carbon emission intensity and GDP per capita，and assess the relationships of carbon emission intensity with economy development and industrial structure. The results show that carbon emission intensities of major industrialized countries increased firstly and then decreased gradually over time，and showing a trend of convergence. On the other hand，carbon emission intensities of major emerging economies were fluctuated with time. The overall trend of world major countries′GDP went upward over time，but the gap between industrialized countries and emerging economies has deepened gradually. Only a few industrialized countries such as USA，UK，France，Germany and Canada showed an inverted Ucurve for the relationship between carbon emission intensity and GDP per capita.China showed an N-curve. South Africa showed an inverted N-curve.Japan，Italy，India，Brazil and Mexico showed an inverted L-curve. The industrialize countries′ (except Canada) secondary industry value add share of GDP and carbon emission intensity were positively correlated，while the emerging economies showed no correlation.