Abstract: The CN_<em>x/TiN multilayer composite coatings were deposited onto stainless steel substrates by combination of DC reaction magnetron sputtering deposition with multi-arc plating. The CN_<em>x/TiN multilayer composite coatings are analyzed using X-ray electron energy spectrum (XPS) and transmission electron diffraction (TED). The liquid impact erosion resistance of stainless steel, high-Cr iron, cobalt-base alloys and CN_<em>x/TiN multilayer composite coatings were researched by using a homemade high-pressure liquid impact erosion tester. Finally, the failure mechanism of CN_<em>x/TiN multilayer composite coatings was studied. The results showed that the multilayer film, with high hardness, strong adhesion and excellent thermal shock resistance, is a good liquid impact erosion resistance coating used in the last stage blade of steam turbines.