The　solidification　of　ettringite　on　the　chromium　ions　with　different　valence　states　and　species　under　the　condition　of　different　sulfate　concentrations　were　investigated　by　means　of　XRD,　IR　analysis,　DSC,　SEM,　ICP　and　other　method.　The　results　showed　that　the　ettringite　solidification　rate　for　the　low　dosage(0.5%)　of　chromium　ions　with　different　valence　and　species　was　add　up　to　85%　or　more.　The　solidification　rate　of　ettringite　to　Cr()　changed　little,　while　the　solidification　rate　to　Cr()　28d　decreased　to　38.6%　when　the　dosage　of　chromium　ions　increased　to　2.0%.　The　solidification　ability　of　ettringite　to　Cr()　was　improved　when　the　concentrations　of　SO42-　ions　were　low　in　the　hydrated　liquid　phase.　No　matter　what　concentration　of　SO42-　ions　was　in　the　hydrated　liquid　phase,　Cr()　and　Cr()　had　a　different　effects　on　the　crystal　structure　and　morphology　of　ettringite,　and　that　of　Cr()　was　more　obvious.　The　effect　of　Cr　ions　on　ettringite　crystal　morphology　was　also　different.　When　the　concentrations　of　SO42-　ions　were　low　in　the　hydrated　liquid　phase,　the　doping　of　Cr()　could　obviously　promote　the　growth　and　development　of　ettringite　crystal　in　the　c-axis　direction,　and　improve　the　crystallization　degree　and　thermal　stability　of　ettringite　to　a　certain　extent.　©　2019,　Editorial　Department　of　Journal　of　Building　Materials.　All　right　reserved.