Structure,　magnetic　properties,　and　thermal　stability　of　ternary　Sm1-x　Tm　(x)　Co-5　compounds　were　studied　via　X-ray　diffraction　(XRD),　thermal　magnetic　analysis　(TMA),　and　magnetic　measurements.　XRD　results　show　that　all　the　compounds　have　a　main　phase　of　hexagonal　CaCu5-type　crystal　structure　with　small　amount　of　impurity　phases;　increasing　Tm　content　is　associated　with　contraction　of　the　hexagonal　unit　cell　in　the　direction　of　the　c　axis　and　expansion　of　the　a　and　b　parameters.　TMA　results　indicate　that　the　Curie　temperature　(T　(C))　of　Sm1-x　Tm　(x)　Co-5　compounds　gets　higher　with　the　increase　in　Tm　content.　Magnetic　measurements　show　that　both　the　magnetic　anisotropy　field　(H　(A))　and　the　magnetization　at　an　applied　field　of　7　T　(M　(7　T))　decrease　with　the　increase　of　Tm　content.　However,　the　thermal　stability　of　both　the　H　(A)　and　M　(7　T)　of　all　the　Tm　doped　compounds　is　remarkably　improved　compared　with　that　of　the　pure　SmCo5　compound,　leading　to　the　result　that　both　the　M　(7　T)　and　H　(A)　of　Sm0.8Tm0.2Co5.2　are　higher　than　those　of　SmCo5　compound　at　473　K,　which　indicates　the　good　potential　of　Tm　doped　compound　in　the　practical　applications　at　elevated　temperature.