A ceramic composite and a method of preparing the same are provided. The method of preparing the ceramic composite includes mixing an aluminum slag and a carbon accelerator to obtain a mixture and reacting the mixture at a temperature equal to or greater than 1600° C. in a nitrogen atmosphere to obtain a ceramic composite. The aluminum slag includes aluminum, oxygen, nitrogen, and magnesium. The weight ratio of the oxygen to the aluminum is 0.6 to 2. The weight ratio of the nitrogen to the aluminum is 0.1 to 1.2. The weight ratio of the magnesium to the aluminum is 0.04 to 0.2. The ceramic composite includes aluminum nitride accounting for at least 90 wt % of the ceramic composite.