Sprayable　feedstocks　were　prepared　by　spray-drying　and　using　alumina-30%　titanium　diboride　composite　powder　mixed　with　10%　nanoscale　alumina　powder　with　a　particle　size　of　80-200　nm,　and　a　titanium　diboride-alumina　composite　coating　was　deposited　by　axial-III　plasma　spraying　system.　The　coating　constitution　and　microstructure　were　analyzed　by　X-ray　diffraction,　scanning　electron　microcopy.　Microhardness　and　Rockwell　Hardness　were　tested　on　the　surface　of　the　coating.　Results　show　that　the　coating　consists　of　α-alumina,　γ-alumina,　titanium　diboride　and　a　small　amount　of　titania;　titanium　diboride　is　mostly　presented　with　particles　in　the　coatings.　The　average　superficial　Rockwell　hardness　of　as-sprayed　coating　is　52.9,　microhardness　of　TiB2　is　16.68　GPa.