Low carbon steel were coated by hot-dipping into a molten bath containing Al-2 wt%Mn, Al-9wt%Mn, Al-13wt%Mn, respectively. The phase composition, morphology and the adhesion of the aluminide layer were characterized by XRD, SEM, EDAX, OM and scratch tester. The results show that the coating layers is mainly composed of Al, FeAl3, Fe2Al5 and MnAl6 phase. The coatings consists of two-layers structure, i.e., topcoat Al-Mn alloy layer and tongue-like intermetallic compound, and the coating layer is about 800 μm thick. The adhesion of the Al-Mn alloy coatings were characterized by Lc value and were found to be about ~30N. The adhesion gradually decrease with the increase of the Mn contents in alloy coatings.