The evolution behaviors ofAl-Fe-Si secondary phase particles in 1235 ultra-thin double zero foil blank during rolling process were observed by TEM. The results shown that bulk secondary phase particles were elongated under the shear stress during rolling process. Meanwhile many small spherical secondary phase particles were concentrated around the elongated bulk secondary phase particles. The major reason for secondary phase particles dissolution and spheroidizing was diffusion process, crystal defects such as high density dislocations and vacancies are the main channels of secondary phase particles dissolution.