Abstract: American Clean Energy and Security Act (ACESA) was passed by the U. S. House of Representatives on June 26, 2009. The bill is the most important climate bill after Liberman-Wanner bill, which was rejected by the House of Senate last year. Contents of the bill may have profound impact on post 2012 international climate negotiation, so it has attracted extensive attention from the international community. In this paper, emission reduction targets, funding mechanisms and adaptation, technology transfer and other issues of the bill are summarized, and international cooperation, the carbon market and carbon tariff issues are also discussed based on the facts in the bill. As a multi-objective and comprehensive proposal addressing climate change by focusing on new energy and energy efficiency improvement actions, the bill is worth learning for facilitating China's transformation to a low carbon development model. At last, some judges and suggestions on how to recognize the bill are also proposed.

Key words: climate change, United States, ACESA, carbon market, carbon tariff