On the basis of sorting out and introducing the greenhouse gas emission reduction program, targets and assumptions that were put forward by the major international organizations, countries, research institutions and some scholars, the paper summarized, compared and comprehensively analyzed the main GHG emission reduction targets, atmospheric concentrations targets of GHG, and temperature control targets of the current international GHG mitigation program. The results revealed that: ①the general control goal of temperature increment proposed by international organizations and major countries was 2 ℃, that is, by the end of the 21st century, the air temperature will be controlled at no higher than 2℃ at the level of preindustrial revolution; ② the GHG mitigation program proposed by international organizations and major countries generally tended to control the atmospheric concentrations of GHG at 450×10-6~550×10-6 CO2e, and there were still large differences in the specific allocation of responsibilities, mitigation measures and emission reductions among each mitigation program; ③when determining the GHG emission reduction targets and allowances, the international organizations and major countries were generally in accordance with the “common but differentiated” principle, tending to set emission reduction targets for developed countries. However however, individual programs considered it necessary for developing countries to take quantified emission reduction commitment obligations.