The　pursuit　of　high-performance　piezo-photocatalysts　through　structural　modifications　has　been　a　focal　point　of　investigation　within　the　realm　of　related　scientific　disciplines.　In　this　study,　we　successfully　designed　Er-doped　Bi0.5Na0.5TiO3–BaTiO3　combined　with　rare　earth　ion　doping　and　solid　solution　modification,　and　the　prepared　particles　exhibited　homogeneous　grain　sizes　and　optimized　concentrations　of　oxygen　vacancies　(OV).　The　synergistic　incorporation　of　OV　(accelerator　for　catalytic　reaction)　and　Er3+　results　in　an　impressive　12-fold　enhancement　of　the　piezo-photocatalytic　rate　when　degrading　the　Rhodamine　B　dye.　The　optimal　composition　0.96BNT-0.04BT-Er　demonstrates　outstanding　electrochemical　properties,　including　a　superior　photocurrent　response　and　minimal　impedance,　highlighting　its　exceptional　performance　in　piezo-photocatalysis.　The　fundamental　enhancement　in　catalytic　performance　can　be　attributed　to　the　reconfiguration　of　the　band　structure　of　0.96BNT-0.04BT-Er,　which　has　been　meticulously　calculated　utilizing　DRS　and　VB-XPS　and　the　internal　mechanism　was　explained　in　detail.　This　research　serves　as　a　source　of　inspiration　for　the　investigation　of　solid　solutions　among　piezo-photocatalysts　and　sheds　light　on　the　vital　role　of　band　structure　in　governing　catalytic　performance.　©　2024　Elsevier　Ltd　and　Techna　Group　S.r.l.