Two experiments were carried out on the same compact strip production (CSP) line, which differs in that one of them experienced γ→α→γ thermal history. The differences in microstructure, precipitation, misorientation etc between two experiments were investigated by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron back-scattered diffraction (EBSD) and positron annihilation technique (PAT). The carbon concentration in matrix is more inhomogeneous in the experiment than that with γ→α→γ7 thermal history. The specific precipitation characteristic in the experiment without γ→α→γ thermal history is discussed on the basis of different carbon diffusion behavior and interaction between dislocation and excess carbon. Two experiments were carried out on the same compact strip production (CSP) line, which differs in that one of them experienced γ → α → γ thermal history. The differences in microstructure, precipitation, misorientation etc between two experiments were investigated by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron back-scattered diffraction (EBSD) and positron annihilation technique (PAT). The carbon concentration in matrix is ​​more inhomogeneous in the experiment than that with γ → α → γ7 thermal history. The specific precipitation characteristic in the experiment without γ → α → γ thermal history is discussed on the basis of different carbon diffusion behavior and interaction between dislocation and excess carbon.