Abstract: As the main gas index on early prediction of coal spontaneous combustion, CO plays a crucial role for the prevention and control of coal spontaneous combustion. However, with the development of the coal mine mechanization level, the enlargement of mining strength, and the improvement of testing method, the CO generation presents multiple source characteristics. CO, generated out of coal spontaneous combustion, seriously interferes the early forecast of coal spontaneous combustion. The source of CO is divided into three categories. The research and application progress of CO generation mechanism and control methods are summarized, which are studied by scholars at home and abroad in recent years. At last, the shortcoming in the existing research are preliminary analyzed and the development trend in future are proposed.