Abstract: An explorative study of hard and multifunction coatings by MOCVD in vertical cold-wall chemical vapour deposition reactor is carried out. Titanium nitride (TiN) and titanium carbonitride (Ti(C,N,)) are formed on stainless steel substrate at. 773. K and 973 K respectively when titanium tetrakisdiethylamide is used at temperature lower than when titanium tetraehloride used. Under the operation conditions, they are verified that the flow pattern is dominated by free convection, deposition is brought about by surface reaction and the reaction activation energy is 237 kJ/mol. Through thermodynamical computation, the mechanisms of chemical reaction at different temperature are proposed.