In　this　paper,　we　report　the　divalent　ions　Mg2+,　Zn2+,　and　Cu2+　as　dopants　to　manipulate　the　crystal　field　asymmetry　in　a　new　cubic　Y3.2Yb0.4Er0.08Al0.32F12　phase　which　features　two　different　coordination　sites　for　rare　earth　ions.　X-ray　powder　diffraction,　transmission　electron　microscopy,　X-ray　photoelectron　spectroscopy,　and　fluorescence　spectrophotometer　were　employed　for　the　crystal　structure　analysis　and　luminescence　performance　investigation.　Results　reveal　that　the　phase　transition　from　cubic　to　orthogonal　of　Y3.2Yb0.4Er0.08Al0.32F12　is　promoted　by　Mg2+　doping.　Among　Mg2+,　Zn2+,　and　Cu2+,　Mg2+　is　found　to　be　the　most　effective　dopant　for　the　upconversion　performance　enhancement.　The　crystal　lattice　structure　asymmetry　increases　with　the　rising　of　Mg2+　doping　concentration　and　reaches　the　peak　when　6　mol%　Mg2+　is　introduced;　correspondingly,　the　brightness　of　408　and　654　nm　emissions　are　strikingly　enhanced　over　20　times,　and　the　lifetime　of　540　nm　emission　is　shortened　to　half　of　that　in　the　Mg2+-free　sample.　The　investigation　results　establish　the　understanding　of　divalent　ions　as　dopants　for　adjusting　upconversion　luminescence　performance　and　may　be　helpful　for　researchers　to　develop　quick　responsive　upconversion　luminescence　materials.