In this paper, pure Ni foil was used as an intermediate layer to achieve brazing connection of 6H-SiC at 1 100~1 245 ℃. The microstructure of the brazed joint and the interface between the brazed joint and the 6H-SiC substrate were studied to investigate the effect of brazing process on the crystal structure of SiC ceramics and provide theoretical and experimental data supports for brazing process design. The results show that a small amount of Ni atoms diffuse into the 6H-SiC ceramics during the brazing process and exist in solid solution form, which reduces the dislocation energy of 6H-SiC. The residual stress at the 6H-SiC/brazed joint interface increases with the increase of brazing temperature, and when the brazing temperature reaches 1 245 ℃, the (0001) plane of 6H-SiC at the interface slips along the 1/3 <1100> direction, and the 6H-SiC is sheared to form 3C-SiC. Therefore, SiC ceramics can undergo phase transformation under the influence of stress and brazing material composition during the brazing process, and the effect of brazing process on their crystal structure and properties should be considered for SiC ceramics used in special environments.