Selective catalytic reduction (SCR) catalyst is a widely used deNOx technology. Different from the review papers on SCR catalysts published in recent years, the preparation method, composition, deNOx ability, influence of flue gas components, and deNOx mechanism of the SCR catalysts were comprehensively discussed according to classification on the different catalyst supports published in the nearly ten years. Meanwhile, the related studies on high-temperature and low-temperature deNOx were also concerned. It shows the unsupported SCR catalyst has lower specific surface area. Metal-based SCR catalysts have relatively good low and high-temperature deNOx performance. Carbon material as a carrier can provide abundant surface area to distribute active elements, and oxygen-containing functional groups on the activated carbon surface can oxidize NO to NO₂. These are beneficial to improve the deNOx ability. The minerals-based SCR catalyst has good deNOx capacity in the middle and low temperature section. Fe, Mn, Ce, V, and Cu are mostly favorable elements for the SCR catalysts with high deNOx ability. The good distribution of active elements, chemical adsorption of oxygen, Lewis or Brønsted acid sites, and abundant surface pore structure on the catalyst surface are important for the catalyst with good deNOx ability. Lastly, the further works are given.