A magnesium-catalyzed asymmetric ring-opening reaction of aziridines with substituted tetrazoles is reported. The current protocol proceeds smoothly and gives the corresponding desymmetrization products in high yields and good enantioselectivities. A new chiral ligand was synthesized from azetidine and (R)-BINOL and was employed in the current in situ generated magnesium catalyst. The Mg(II)-mediated desymmetrization reaction could be performed on gram scale under mild conditions and was transformed to chiral alkyl amines by a deprotection process.