Tuning　the　luminescent　properties　of　phosphors　by　crystal-site　engineering　is　a　good　and　efficient　strategy　for　developing　high-quality　white　light-emitting　diodes　(WLEDs).　However,　it　is　still　challenging　to　modulate　the　cyan　to　red　spectral　emission　in　a　single　matrix　and　activator　phosphor　to　obtain　multicolor　output　and　achieve　full-visible-spectrum　lighting.　Herein,　the　strategy　to　manipulate　site-selective　occupation　of　Eu2+　activators　by　substituting　the　cation　Rb+　with　K+　is　reported　to　obtain　a　versatile　color　output.　The　large-scale　redshift　regulation　of　emission　spectrum　from　cyan　to　red　was　achieved　in　fluor-phosphate　Rb2-yKyCaPO4F:　0.0085Eu(2+)　(R2-yKyCPOF:　0.0085Eu(2+))　(0　＜=　y　＜=　1.8)　phosphors,　which　is　designed　by　using　Rb2CaPO4F:　0.0085Eu(2+)　(RCPOF:　0.0085Eu(2+))　cyan-emitting　phosphor.　The　redistribution　of　Eu2+　ions　in　Rb1,　Rb2,　and　Ca　sites　is　achieved　by　introducing　the　cation　K+　to　substitute　Rb+,　and　R2-yKyCPOF:　0.0085Eu(2+)　(0　＜=　y　＜=　1.8)　is　kept　in　the　pure　phase.　Furthermore,　the　mixed　phosphors　of　RCPOF:　0.0085Eu(2+),　RKCPOF:　0.0085Eu(2+),　and　R0.2K1.8CPOF:　0.0085Eu(2+)　show　excellent　optical　performance　and　good　thermal　stability.　Full-visible　spectrum　lighting　is　successfully　achieved　with　the　combination　of　a　395　nm　NUV　chip　and　the　blend　of　phosphor-converted　WLEDs.　The　K+　substitution　reported　in　this　paper　can　support　a　project　for　warm　WLEDs　by　manipulating　the　distribution　of　Eu2+　activator　among　different　cation　sites.