The　selective　catalytic　reduction　(SCR)　of　NOx,　utilizing　carbon　monoxide　(CO)　and　ammonia　(NH3),　is　recognized　as　an　effective　approach　for　NOx　abatement.　During　the　SCR　process,　the　appropriate　pretreatment　of　catalysts　can　significantly　enhance　their　surface　and　interfacial　structures,　thereby　improving　their　activity,　selectivity,　and　stability.　This　review　begins　with　the　reaction　mechanisms　of　CO-SCR　and　NH3-SCR,　followed　by　an　introduction　to　various　pretreatment　strategies　that　can　enhance　the　performance　of　catalysts　employed　in　these　two　reactions.　An　in-depth　discussion　is　provided　regarding　how　different　pretreatment　methods　influence　the　active　structure　of　catalysts,　the　key　steps　of　the　reactions,　and　the　overall　catalytic　performance.　Subsequently,　a　comparative　analysis　of　the　pretreatment　strategies　employed　for　both　reactions　is　presented,　highlighting　their　similarities　and　differences,　thereby　elucidating　the　essence　of　pretreatment　techniques.　Lastly,　the　paper　identifies　the　current　challenges　encountered　in　the　field　of　pretreatment　and　proposes　potential　directions　for　future　development.　This　work　aims　to　offer　theoretical　insights　that　may　inspire　innovative　pretreatment　strategies　in　CO-SCR　and　NH3-SCR　among　researchers　and　engineers.