Abstract: The influence of different iron-rich phases on the mechanical properties of aluminium alloys has been a hot topic of research, but in situ analysis of the deformation behavior of different iron-rich phases during stressing is relatively blank.The A380 aluminum alloy was modified by using 0.5wt%Mn.The A380-0.5Mn alloys with fishbone α-Fe, bulk α-Fe and needle-like β-Fe were obtained.The microstructure deformation behavior during the stress process was studied by in situ tensile analysis combined with DIC (digital image correlation method), and the deformation mechanism of different Fe-rich phases was summarized by fracture analysis. The results show that there is a small strain in both the fishbone α-Fe and the surrounding matrix, and the dislocation movement is a cut-through mechanism, which can improve the strength and plasticity.The bulk α-Fe has no obvious strain and there is micro-strain around it, and the dislocation motion is a bypassing mechanism, which can improve the strength. The needle-shaped β-Fe in the parallel tensile direction and the surrounding matrix all have large strains, which produce internal micro-cracks and deteriorate the properties by forming new phase boundaries; the needle-shaped β-Fe in the perpendicular tensile direction has small strains and the surrounding matrix has large strains, which are due to dislocation accumulation and stress concentration leading to cracking.