To provide a synthesis method of TiC-based nanocomposite by which TiC,TiCN powder or TiC+Ni(Co,Al), TiCN+Ni(Co, Al) composite ultrafine particle nanocomposite powder is more economically synthesized with higher quality by the metal thermal reduction method.

The synthesis method of the TiC-based nanocomposite powder by the metal thermal reduction method includes at least the following processes, which are a process for preparing a mixed solution of titanium tetrachloride (TiCl4) with carbon chloride, a process for charging the mixed solution into a tightly closed vessel in which molten magnesium (Mg) or a molten magnesium alloy is housed under an inert atmosphere, a process for vacuum-separating remaining excess liquid Mg and magnesium chloride (MgCl2) after magnesium reduction reaction in the tightly closed vessel and a process for recovering TiC and TiCN or a synthesized product in which alloy components (Ni, Co, Al) are incorporated in TiC and TiCN, from the tightly closed vessel after the vacuum separation of the liquid Mg and MgCl2. In the synthesis method, inexpensive titanium chloride and carbon chloride are used and TiC and TiCN powder or composite powder containing Ni, Co and Al components in TiC and TiCN which have several 10 nm particle size are synthesized in relatively simple processes.