The synthesis process and the formation mechanism of Al₄SiC₄ were investigated using Al, Si, and C as starting materials. Properties such as hydration resistance of the synthesized Al₄SiC₄ were examined. SiC and Al₄C₃ begin to form from about 800°C and 900°C, respectively. When the temperature is above 1300°C, both products further react with each other to form Al₄SiC₄. With increasing temperature and time, the formation ratio of Al₄SiC₄ increases. The addition of Al₂O₃ can facilitate the formation of Al₄SiC₄. The hydration resistance of Al₄SiC₄ is excellent and sufficient for the practical use.