<p>During the later stages of oilfield development, CO₂ flooding is employed as a critical strategy to enhance oil recovery. The acidic nature of produced fluids imposes stringent requirements on the corrosion resistance of sucker rods. The premature failure of sucker rods results in significant economic losses and operational challenges for the oilfield industry. This paper presents an in-depth analysis of the fracture failure mechanism of 00Cr12 stainless steel sucker rods used in a CO₂-flooded producer well at Shengli Oilfield. Research findings reveal that 00Cr12 sucker rods, when subjected to prolonged exposure in downhole environments, exhibit severe pitting corrosion on their surfaces. Specifically, the interaction between pitting corrosion and surface porosity or inclusions results in the formation of relatively deep pitting pits. Under the influence of reciprocating cyclic stress, cracks nucleate and propagate, ultimately leading to material failure, which is identified as the primary cause of this phenomenon. In the solution environment, H⁺ ions are reduced to active hydrogen atoms. These atoms subsequently adsorb onto the surface of 00Cr12 stainless steel and diffuse into its matrix. Hydrogen atoms tend to accumulate at stress concentration sites, thereby accelerating crack propagation. The increased hydrogen content induces a rise in material brittleness and a reduction in toughness, which constitutes another critical factor contributing to the fracture of sucker rods. Optimizing the casting process of sucker rod raw materials to minimize the presence of pores and inclusions, while enhancing the base material’s resistance to pitting corrosion and hydrogen embrittlement, can significantly prolong the service life of the sucker rods.</p>