Abstract: With plasma as heat source, Fe-based alloy powder was cladded on the surface of 16Mn steel and the microstructure and phases of the clad coating were analyzed. The thermal cycle characteristics of plasma cladding and the cladding process were discussed. The heat-affected zone was studied and divided into three zones, i.e., overheated zone, perfect phase transformation zone and imperfect phase transformation zone. In the overheated zone, the microstructure was coarse, Widmanstaten structure generated and the hardness fell down. In the perfect phase transformation zone, the microstructure was refined, and hardness was higher. In the imperfect phase transformation zone, part phase transformation generated, and the microstructure was nonhomogeneous. The Widmanstaten structure in the overheated zone made the heat-affected zone brittle.