The　bound　rubber　measurement　method　was　improved　by　ethylenediamine　(NH2-CH2-CH2-NH2)　replacing　ammonia　(NH3)　as　the　basic　agent.　Using　the　new　method,　the　influence　of　organic　base　on　bound　rubber　content　was　investigated,　the　relation　between　bound　rubber　content　and　the　mechanical　properties　of　the　silicone　rubber　filled　with　modified　ultrafine　mineral　powder　was　studied,　and　the　interaction　between　silicone　rubber　matrix　and　mineral　filler　was　discussed.　As　a　result,　it　is　suggested　that　chemical　interaction　plays　the　main　role　in　the　bound　rubber　of　silicone　filled　with　modified　ultrafine　mineral　powder.