On the basis of analyzing the evolution of major countries' climate negotiating positions in chronology, the implementation of major countries' emission reduction targets promised in the Kyoto Protocol and the long-term emission reduction targets by 2025 or 2030 are assessed. The results show that the enthusiasm to address climate change issues in the U.S., Canada, Australia, which are members of the Umbrella Group, is relevant to the political Party in power. Considering current ruling Parties of these three countries, they have shown negative positions to reduce emissions. The emission reduction rate in U.S., Canada, and Australia by 2030 would be less than 20% compared to 1990 level, which is much lower than the 40% reduction rate of the European Union by 2030. BASIC countries gradually transformed into active participants from initial opponents in international negotiations. China not only commits to achieve the peaking of CO_2 emissions around 2030,but also announces to provide finance for mitigations in other developing countries. The emission in South Africa will keep stable by 2025, but may rise after 2025. Brazil is active and ambitious in climate negotiation due to the reducing greenhouse gas emissions from deforestation and forest degradation, showing a significant decline in emissions by 2030. However, the emission in India will still keep increasing by 2030.