The　evaporation　of　both　CeO2　and　La2O3　in　high　temperature　plasma　arc　leads　to　deviation　of　plasma　sprayed　La2Ce2O7　coating　composition　from　the　starting　powder　particle.　Such　change　results　in　significantly　inhomogeneity　of　compositions　within　a　coating　which　influences　the　performance　of　calcium-　magnesium-alumina-silicate　(CMAS)　corrosion.　In　this　study,　the　pellets　with　different　Ce　/　La　ratio　were　interacted　with　molten　CMAS　glass.　The　penetration　of　molten　CMAS　on　different　pellets　was　characterized　by　scanning　electron　microscopy　and　energy　dispersive　spectrum　(EDS)　and　the　phase　of　different　powder　mixtures　treated　at　1250　°C　was　characterized　by　X-ray　diffraction　(　XRD　).　The　effects　of　pellets　with　different　Ce　/　La　ratio　on　the　CMAS　corrosion　after　thermal　exposure　at　1250　°C　for　50　h　were　investigated.　The　result　demonstrated　that　pellets　with　ratio　of　Ce　/　La　greater　than　or　equal　to　1.0　were　completely　dissolved　into　the　molten　CMAS,　at　the　same　time　the　others　were　also　damaged,　forming　diffusion　layer　and　reacted　layer,　respectively.　The　difference　of　the　ratio　of　Ce　/　La　indeed　affected　their　performance　against　CMAS　attack.　©　(2015)　by　ASM　International　All　rights　reserved.