Abstract: The regulator tank is filled with fire water for rapid response to a fire accident, helping complete the fire fighting action. The coating of a fire control water regulator tank in a nuclear power plant was found to have failed during regular inspection. Serious corrosion had occurred to the tank wall, the outlet valve of the tank bottom and the pipeline. The corrosion was mainly caused by coating damage. Occlusive battery corrosion occurred to the matrix, but each has its own characteristics, so the actual maintenance analysis should be carried out according to the actual situation. It is recommended that the valve be replaced, tank corrosion pits be repaired, and coating be re-brushed, so that the corrosion perforation can be prevented, and the normal operation of fire protection systems can smoothly run.