This paper surveys the present status and the perspective of de-NOx SCR catalysis for stationary sources, that is based on the reduction of NOx by NH3 to form water and nitrogen. After a brief description of the SCR chemistry the characteristics of commercial SCR catalysts, their physico-chemical properties and reactivity, and their performances in both NOx reduction and SO2 oxidation are presented. The mechanism of the SCR reactions, the mathematical modeling of the reactor and the arrangements of the reactor and process are then described. Finally the emerging technologies for NOx removal and the future perspectives of the SCR catalysis are outlined.