Fe has been a main concern in recycling Al materials due to its obvious deleterious effect on alloy’s ductility. While, benefitting from the excellent ductility of Al-Mg matrix, Al-Mg based alloy provides an opportunity to develop high-Fe alloys with balanced strength and ductility. In this paper, the morphology, growth mechanism of Fe-rich phases in HPDC Al-5Mg-xFe and Al-5Mg-0.6Mn-xFe alloys were studied. It was found Fe forms Al-Al13Fe4 eutectic and large strip-like primary Al13Fe4 phase in Al-Mg-Fe alloys. In Al-Mg-Mn-Fe alloys (Fe<=1.0%), Fe exists in normal Al-Al6(Fe,Mn) eutectic. When Fe level is more than 1.0%, primary Al6(Fe,Mn) phase with a hollow tube prismatic morphology appears. Meanwhile, eutectic Al6(Fe, Mn) phase is also completely divorced with Al and shows a nano-scaled solid tube prismatic morphology. It is revealed the growth morphologies of primary and eutectic Al6(Fe,Mn) phases are controlled by bulk diffusion mechanism. The mechanical properties of Al-Mg-Mn-Fe alloys were also tested.