Titanium nitride (TiN) films were successfully deposited on ρ-type Si (100) and (111) substrates by atomic layer deposition (ALD) method at 450°C. In this ALD system, the TiCl4 and NH3 gases were supplied, separately and Ar purge gas was added between the source and reactant gases to suppress the direct reaction. The main purpose of this study is to investigate the properties of TiN film grown by ALD method. To investigate the growth mechanism, the growth model of TiN was suggested for the calculation of growth rate per cycle with Cerius program. The results of calculation by the model were compared with experimental values of the TiN film deposited by ALD method. TiN films deposited on Si (100) and (111) substrates were examined by TEM and showed the randomly oriented columnar structure. The thickness of TIN film deposited on Si(111) substrate was slightly thicker than that of TiN film deposited on Si(100) substrate. Chlorine content in both TiN films was below the detection limit of AES (<lat%). And the densities of TIN films deposited on Si (100) and (111) substrates were 4.85g/cm3 and 4.98g/cm3. which are higher than that of the films deposited by other conventional CVD methods.