The　feasibility　of　utilizing　molybdenum　tailing　and　diatomite　as　siliceous　materials　to　prepare　calcium　silicate　board　was　explored.　The　influences　of　molybdenum　tailing/diatomite　proportion　on　hydration　characteristics,　thermal　conductivity,　water　absorption,　flexural　strength　and　moisture　adsorption-desorption　property　of　calcium　silicate　board　were　investigated　in　detail.　The　experimental　results　reveal　that　molybdenum　tailing　is　environmentally　friendly　to　prepare　building　materials.　The　main　hydration　products　in　calcium　silicate　board　under　autoclaved　condition　are　C-S-H　with　low　crystallinity　and　tobermorite.　Molybdenum　tailing　is　favorable　to　the　formation　of　tobermorite.　The　flexural　strength　and　bulk　density　of　the　calcium　silicate　board　gradually　increase　when　the　content　of　molybdenum　tailing　increases.　Netlike　C-S-H　is　formed　with　the　increase　of　diatomite　content　during　autoclaved　curing　process,　resulting　in　the　enhancement　of　moisture　adsorption-desorption　performance　and　the　reduction　of　thermal　conductivity.　The　optimal　content　of　molybdenum　tailing　is　20%,　furthermore,　the　flexual　strength　and　thermal　conductivity　of　calcium　silicate　board　at　this　content　meet　the　Chinese　standard　JC/T564.1-2008.