Abstract: In response to the large deviation in water production and extremely low cycle water production of 6 high-speed mixed beds in the condensate polishing system of a 2x60MW coal-fired unit, the causes were analyzed through methods such as on-site observation of operation status, internal disassembly inspection of equipment, and verification of regeneration system performance. results show that there are differences in the winding gap of the water inlet cap on the upper part of the 4A mixed bed, and the cap with a smaller gap is seriously by resin, resulting in uneven water distribution and inlet water diversion, which is the core cause of low water production. In view of the root cause of the problem, targeted such as replacing the water cap with a winding gap of 1.02mm with a water cap of 1.2mm, regular inspection and maintenance, optimizing the control resin quantity, and standardizing the criteria for judging the failure of mixed beds were proposed. After implementation, the cycle water production of the 4A mixed bed increased by 45 times.