Currently, the term "carbon accounting" has been widely used in various fields, especially when the climate change puts into the discussion of accounting. However, academia is still no common understanding of carbon accounting. Based on the comprehensive literature review of international carbon accounting, this paper classifies these papers into four levels: the international carbon accounting research, projects, organizations and product level, and each level has monetary and non-monetary research. This paper systematically illustrates the purpose and content of the international carbon accounting research, proposes a broader definition of carbon accounting based on the evaluation of the characteristics of these studies, and indicates the future trends of the carbon accounting research.