The crevice corrosion behavior of super 13Cr stainless steel in saturated CO₂ oilfield produced fluids in conditions of varying crevice opening widths was investigated using immersion test and electrochemical techniques. The results indicated that under CO₂ pressure of 1.5 MPa at 60 ℃, crevice corrosion behavior of super 13Cr was primarily governed by the cathodic process related with CO₂ hydrolysis products. With the increase in the width of the crevice opening, the crevice corrosion rate of super 13Cr increases, while the Cr₂O₃ within the passivation film gradually transformed into Cr(OH)₃. When the crevice width was 0.125 mm, substances exchange between the inside and outside of the crevice was restricted. The depletion of cathodic reducing agents within the crevice inhibited the cathodic reaction, allowing the metal to remain in a passivated state with no occurrence of significant corrosion. At a crevice width of 0.25 mm, material exchange between the inside and outside of the crevice was enhanced. Due to the influence of CO₂ hydrolysis products, the passive film within the crevice underwent anodic dissolution, leading to the formation of pitting and an increase in the crevice corrosion rate. When the crevice width was 0.5 mm, a critical concentration of Cl^- was reached within the crevice, inducing the dissolution of inclusions and subsequent pitting corrosion. Despite these changes, in conditions of pitting corrosion and within a range of the entire tested opening crevice widths, super 13Cr all exhibited passivation performance, forming a surface film composed mainly of Cr₂O₃ and Cr(OH)₂. Regardless of the crevice width, corrosion products tended to accumulate at the crevice openings; however, their impact on the material exchange remained relatively minor. The elevated concentrations of H⁺ and Cl^- near the crevice opening promoted pitting corrosion of the metal outside the crevice.