Greenhouse gases(GHG) emission databases are the basis for the assessment of the greenhouse gases emission and the obligation negotiation of mitigation of greenhouse gases emission. Based on our survey of the global greenhouse gases databases worldwide, some primary organizations that built the important referenced databases were investigated. They are US Energy Information Administration, World Resource Institute, Carbon Dioxide Information Analysis Center, UNFCCC, and International Energy Agency of OECD. The situations of the five organizations, the characters of their databases as well as their usability and difference were compared and studied. Some related questions, such as why it is important to increase the reality and coverage, what the limitation of the current databases is, etc, ware discussed at the end of this paper. Some suggestions were provided finally.