Reactor structural materials at high temperatures and pressures in prolonged contact with the coolant will produce corrosion products, which are deposited on the surface of the equipment metals and can cause adverse effects such as reduced heat transfer efficiency, axial power migration and locally high radiation fields. The main in-service chemical decontamination processes currently used in engineering are HP/CORD, CAN-DEREM^(TM), CITROX, LOMI, EMMAC, SP-HyBRID and Ce( IV ), and decommissioning decontamination processes are DfD, ASDOC_D and MEDOC. This paper provides an overview of the current research status and engineering applications of several typical in-service and decommissioning chemical decontamination processes, and provides indicative suggestions for subsequent research on decontamination technologies.