Abstract: Co106F powder was deposited on the valve surface of 304 stainless steel, F51 duplex stainless steel and A105 carbon steel by plasma surfacing technology. The surfacing layers on the surface of three kinds of substrate materials were analyzed by metallographic examination, line scanning analysis and hardness test. The results show that the fusion line of the surfacing layer on the valve surface of the three matrix materials was straight, but there were defects. Between the fusion line and the matrix, the elements such as Co, Cr and Fe in the surfacing layer of the valve surface of the three matrix materials all diffused. After plasma surfacing Co106F powder, the hardness increasement of the surfacing layer on the surface of A105 carbon steel valve was obvious.