The invention discloses a chiral imidazoline sulfur ligand and a synthesis method thereof. The synthesis method comprises the following steps: adopting 1-bromine-2-imidazoline benzene or 1-bromine-2-imidazoline naphthalene as a starting material; treating the starting material with n-BuLi, and conducting reaction on the starting materials with diphenyl dithioether; adding 10% of a NaOH solution; carrying out extraction; carrying out drying; carrying out concentration; carrying out chromatograph to obtain the novel chiral imidazoline sulfur ligand. The synthesis method provides a simple and feasible method for synthesis of chiral imidazoline sulfur ligand, and provides convenience for research and wide application of the chiral imidazoline sulfur ligand; besides, the compound can be used for an asymmetric catalytic reaction as a chiral ligand.