Using　the　industrial　limestone,　fly　ash　and　pure　chemical　reagents　as　raw　materials,　the　blast　furnace　slag　was　prepared　by　the　fast　air-cooled　method.　Using　orthogonal　experiment　method,　the　influence　of　process　conditions　such　as　heating　rate,　heat　preservation　time　of　the　blast　furnace　slag　in　hearth,　discharge　temperature　of　slag　and　cooling　speed　on　the　glass　content　and　hydraulic　activity　of　blast　furnace　slag　were　studied,　the　main　influence　factors　and　the　optimal　process　conditions　of　blast　furnace　slag　were　determined.　The　results　showed　that　the　discharge　temperature　of　slag　was　the　key　factor　influencing　on　the　glass　content　of　granulated　blast　furnace　slag.　The　impact　degree　of　all　process　conditions　on　the　glass　content　of　granulated　blast　furnace　slag　accord　with　the　following　sequence:　discharge　temperature　of　slag　＞　heat　preservation　time　＞　heating　rate　＞　cooling　rate.　And　heat　preservation　time　and　cooling　rate　were　the　key　factors　influencing　28　days　activity　index　of　blast　furnace　slag,　the　impact　sequence　of　all　process　conditions　on　the　28　days　activity　index　of　granulated　blast　furnace　slag　was　as　follows:　heat　preservation　time　＞　cooling　rate　＞　discharge　temperature　of　slag　＞　heating　rate.　This　study　also　optimized　the　process　conditions　of　granulated　blast　furnace　slag　for　different　indicators.　©　(2015)　Trans　Tech　Publications,　Switzerland.