Abstract: Compressive strength of non-sintered steel slag ceramsite，being added of different reagents of NaOH，CaO，gypsum，CaCl₂，sodium silicate，curing at 3,7,28 d are detected.Effect of various activators on the compressive property of non-sintered steel slag ceramsite is analyzed and compared.The hydrate products of steel slag generated after activation are finally determined by XRD analysis.The test results show that the activators can destroy the vitreous network structure of the steel slag and release active ingredients sealed inside，such as ferro-silico aluminium，among which，the composite activator made up of NaOH and gypsum（ratio of which is 1∶1) has the best activation effect on non-sintered steel slag ceramsite.Activated by this activator，the hydrated mineral phase generated from steel slag is hedenbergite.

Key words: Steel slag, Non-sintered ceramsite, Activator, Compressive strength