Mg-Al-Cl hydrotalcite was synthesized succesfully using coprecipitation method with high supersaturation condition. The obtained material was characterized by using X-ray difftaction, Fourier transmision infrared, field emission scanning electron microscopy, energy-dispersive X-ray analysis, and thermal analysis. The effects of reaction temperature and ratio of starting salts on the phase structure of the material were investigated. The material has remarkable ability to remove nitrate ion from aqueous solution by ion exchange process. It is however incomparable to Mg-Al-Cu/CO3 hydrotalcite.