To　solve　the　problem　of　low　cementitious　activity　of　steel　slag　(SS),　N,　N-bis(2-hydroxyethyl)-2-aminoethanesulfonic　acid　sodium　salt　(BES-Na)　and　triethanolamine　(TEA)　were　used　in　this　study　to　improve　the　hydration　activity　of　SS.　However,　there　are　no　comparative　studies　on　the　effects　of　BES-Na　and　TEA　on　the　hydration　of　SS-Portland　cement　(PC)　systems.　This　study　compared　the　hydration　process　and　strength　development　of　SS-PC　systems　in　the　presence　of　BES-Na　and　TEA,　as　well　as　the　complexing　ability　of　BES-Na　and　TEA.　The　results　showed　that　both　BES-Na　and　TEA　improved　the　early　compressive　strength　of　SS-PC　mortar,　but　TEA　did　not　contribute　to　the　late　compressive　strength,　while　BES-Na　still　improved　the　late　compressive　strength.　At　the　same　dosage,　TEA　accelerated　aluminates　hydration　more　than　BES-Na　and　retarded/inhibited　silicates　hydration　more　than　BES-Na.　This　difference　in　effect　on　hydration　can　be　attributed　to　the　difference　in　their　complexing　ability.　TEA　has　a　stronger　complexing　ability　with　metal　ions　than　BES-Na,　which　is　beneficial　for　accelerating　aluminates　hydration,　but　this　not　only　prolonged　the　hydration　induction　period　but　also　inhibited　silicates　hydration.　BES-Na　has　a　weaker　complexing　ability　relative　to　TEA.　Although　BES-Na　has　a　weaker　accelerating　effect　on　aluminates　hydration,　it　has　a　lesser　effect　on　silicates　hydration　and　even　accelerates　silicates　hydration　at　low　dosage.　This　study　also　showed　that　BES-Na　is　an　alternative　additive　to　TEA,　which　could　help　expand　the　application　of　BES-Na　in　cementitious　materials.