Abstract: The corrosion resistance of 011/011 near singular grain boundaries is significantly better than that of random grain boundaries. Optimizing and increasing the proportion of such grain boundaries through grain boundary engineering may become an effective way to improve the intergranular corrosion resistance of body centered cubic metals, especially low chromium ferritic stainless steel. In this study, hot forged 00Cr12 steel was used as the test material. Five parallel samples were subjected to one pass rolling with a thickness reduction of 35% in the γ phase region at 960 ℃, and then quickly placed in a muffle furnace at 700 ℃ for tempering for 0.5, 1, 2, 3, and 4 h respectively, followed by water quenching to room temperature. To quantitatively calculate the proportion of 011/011 near singular grain boundaries in each sample, a grain boundary inter-connection characterization method based on electron backscatter diffraction （EBSD） technology combined with five parameter analysis was adopted. The results show that with increasing tempering time, the proportion of 011/011 near singular grain boundaries does not change monotonically. It first increases and then decreases, reaching a maximum value of 10.97% after tempering at 700 ℃ for 2 h. Offline in situ EBSD results further reveal that there are two main mechanisms for the formation of 011/011 near singular grain boundaries. One is that grains that are not originally adjacent but have an orientation relationship of 〈011〉/θ collide with each other by swallowing intermediate grains during tempering at 700 ℃, thus forming 011/011 near singular grain boundaries. The other is that adjacent grains undergo orientation difference adjustment and grain boundary plane reorientation during tempering, generating 011/011 near singular grain boundaries. When tempering at 700 ℃ for more than 2 h, abnormal grain growth occurs. The migration of high angle grain boundaries swallows part of the 011/011 near singular grain boundaries, leading to a decrease in the proportion of such boundaries.