In the current environment concerned world economy, environmental costs became the pervasive topic affecting local, national and global economic developments. Through using the Cause-Effect Analysis, the author found out that a consequence from the externality of environmental costs is the market failure. Considering various environmental costs need to be differently measured, the author selects a case of CO? emission, which incontestably causes a kind of environmental costs. To internalize this kind of costs, CO? trading is most valuable being concerned, and it has been successfully applied in some of developed countries, especially in EU. For China, the author suggests an integrated method of CO? emission tax and CO? trading; the Clean Development Mechanism to balance the worldwide CO? credit trade; as well as the Green Manufacture to consolidate environmental costs during the production process. Those implementation approaches for internalizing the environmental cost incurred by CO? emission in China are recommended in this book. The author hopes this research could be shared with scholars who are interested in environmental cost related subjects.