Copenhagen Climate Summit which was designed to sign a new agreement on the future global action to reduce emissions of greenhouse gases after the expiry of the first commitment phase of “Kyoto Protocol” in 2012 , ending up with a nonlegally binding document named “Copenhagen Accord” The provisions in “Copenhagen Accord” about the limit of global warming,fund,technology and the issue of transparency which were based on the principle of “common but differentiated responsibilities” and the “twintrack” negotiating mode provide a starting point for the further negotiations The “Copenhagen Accord” has legal limitations on the procedure , the content and the legal effect of the accord itself Therefore, how to turn the political will in “Copenhagen Accord” to legally binding rights and obligations has become the biggest challenge in the followup negotiations