The　blue-green　emitting　La2MgZr1-xSnxO6:　0.02Bi3+　(x　=　0–1,　abbreviated　as　LMZ:　Bi3+,　xSn4+)　phosphors　with　a　double-perovskite　structure　were　prepared　through　a　conventional　high-temperature　solid-state　method.　A　complex　ionic　substitution　phenomenon　of　selective　occupation　of　Bi3+　in　the　host　of　LMZ　was　observed　with　Sn4+　doping　which　was　explained　on　the　basis　of　Rietveld　refinement,　density　functional　theory　(DFT)　calculation　and　UV–vis　spectroscopy　results.　Fluorescence　spectrum　analysis　showed　that　LMZ:　0.02Bi3+　emitted　a　broad　green　light　band　with　a　range　of　375–650　nm.　With　the　increase　of　the　Sn4+　concentration　replacing　Zr4+,　the　intensity　of　green　light　was　firstly　enhanced　and　then　gradually　decreases　until　disappeared.　The　emission　peak　of　blue　light　appears　near　400　nm　and　then　its　intensity　gradually　increased.　Through　Gaussian　deconvolution　and　fluorescence　decay　curve,　it　was　found　that　there　were　two　luminescence　centers　in　LMZ:　0.02Bi3+,　and　three　luminescence　centers　in　LMZ:　0.02Bi3+,0.6Sn4+,　respectively,　which　were　determined　by　the　Van　Uitert　empirical　formula　combined　with　the　energy　level　splitting　theory.　The　above　results　demonstrate　that　how　to　tune　emission　color　by　the　substitution　of　B-site　in　double　perovskite　phosphors,　which　is　attractive　for　future　applications.　©　2022　Elsevier　B.V.