Abstract: Taking the sealing ring screws of critical plant water pumps as the research object, this study analyzes the causes of screw fracture through various methods such as macroscopic inspection, chemical composition analysis, metallographic examination, hardness testing, and microscopic analysis of fracture surfaces. The results show that the primary reason for the fracture of the sealing ring screws is the poor water corrosion resistance of their material, evidenced by distinct pits of pitting corrosion on both the surface and cross-section of the fractured screws. Additionally, factors such as electrochemical reactions and excessive bolt hardness contribute to the fatigue fracture failure under alternating loads. It is recommended that the screw material be replaced with duplex stainless steel to enhance water corrosion resistance and prevent electrochemical corrosion.