In order to better understand the formation mechanism of tertiary oxide scale in high-strength steel during hot rolling, the microtexture of the oxide layer has been characterized and analyzed by the electron backscatter diffraction (EBSD) method. The results show that the Fe₃O₄ phase in the oxide layer has a two-phase heterogeneous morphology, Fe₃O₄ in the oxide layer comprises columnar grains, and Fe₃O₄ near the substrate comprises spherical grains. As the reduction rate increases, the Fe₂O₃ layer is gradually wedged into the surface of the Fe₃O₄ layer. Fe₃O₄ forms a fiber texture at a reduction rate of 10%. The inner layer of the oxide scale comprises spherical grains, and Fe₃O₄ is preferentially nucleated and precipitated in the direction of Fe surface grains texture. With the increase in the reduction rate, the {112}<−1−21> directional slip system shows the lowest Schmidt factor value, so the grains with a low Schmidt factor exhibit higher stored strain energy. The formation of the spherical Fe₃O₄ seam layer close to the steel matrix is the result of the combined effect of the stress state at the matrix and ion diffusion.