In　recent　years,　optical　limiting　(OL)　materials　based　on　nonlinear　optical　effects　have　been　widely　used　in　military,　optical　engineering　and　scientific　research　fields.　Pb-based　perovskite　quantum　dots　(QDs)　materials　are　regarded　as　potential　OL　materials　due　to　its　excellent　linear　and　nonlinear　optical　properties,　resulting　from　the　lone　pair　orbital　6s2　of　Pb.　However,　the　larger　OL　threshold　and　toxicity　of　Pb　limit　its　wider　applications.　Herein,　Cs3Sb2Br9　QDs　were　synthesized　by　supersaturated　crystallization　method,　in　which　Sb　has　the　same　solitary　pair　orbit　as　Pb.　The　nonlinear　optical　absorption　(NLA)　and　OL　characteristics　are　studied　by　using　the　open-hole　Z-scan　technique　under　the　irradiation　of　532　nm　laser.　The　NLA　coefficient　is　recorded　as　beta　=　62　cm　GW-1,　which　is　three　orders　of　magnitude　larger　than　CsPbBr3　nanocrystals　(NCs),　and　the　OL　threshold　is　derived　as　Fth　=　2　J　cm-2,　which　is　better　than　other　OL　materials　reported　in　the　literatures,　rooting　in　free　carrier　absorption　(FCA)　under　different　laser　energies.　In　general,　these　results　indicate　that　Cs3Sb2Br9　QDs　can　be　a　potential　superior　candidate　as　OL　material　for　practical　expansive　applications.