Abstract: Co-Mo based catalysts can be widely used in petrochemical, coal based chemical and fertilizer industries. Recently, many excellent Co-Mo based commercial catalysts have been exploited out by means of Preparation-process innovation, active components and/or additives adjustments and new type of support introduction. In this paper, the features of Co-Mo based sulfur-tolerant CO shift catalyst are characterized by using of Micro-Reactor, Temperature-Programmed Reduction (TPR), Temperature-Programmed Sulfurization (TPS) and in-situ IR techniques. It is found that there are two kinds of active sites on the Cu-Mn/Al2O3 catalysts, one is Cu or Mn, and the other one is formed via their interaction. The catalytic activity is contributed to both of the two kinds of the active sites.