A method for making a transition metal dichalcogenide crystal having a chemical formula represented as MX2 is provided, wherein M represents a central transition metal element, and X represents a chalcogen element. The method includes providing a MX2 polycrystalline powder, a MX2 seed crystal, and a transport medium. The MX2 polycrystalline powder and the transport medium are placed in a first reaction chamber. The first reaction chamber and the MX2 seed crystal are placed in a second reaction chamber having a source end and a deposition end opposite to the source end. The first reaction chamber is placed at the source end, and the MX2 seed crystal is placed at the deposition end.