The　extensive　use　of　selective　catalytic　reduction　(SCR)　catalysts　will　afford　many　spent　SCR　catalysts.　The　mass　fraction　of　the　titanium　component　is　over　80%　in　spent　SCR　catalysts,　but　currently,　it　is　usually　thrown　away　without　proper　recycling.　This　work　aims　to　develop　a　clean,　green,　and　economical　approach　to　recovering　titanium　and　regenerating　TiO2　photocatalysts　from　spent　SCR　catalysts　based　on　the　conversion　of　the　titanium　component.　This　titanium　component　is　converted　into　metastable　alpha-Na2TiO3　with　high　efficiency　(＞98%)　using　a　NaOH　molten　salt　method,　and　the　optimal　conditions　were　found　to　be　a　roasting　temperature　of　550　degrees　C,　a　NaOH-to-spent-SCR-catalysts　mass　ratio　of　1.8:1,　a　roasting　time　of　10　min,　and　a　NaOH　concentration　of　60-80　wt　%.　And　a　possible　chemical　reaction　mechanism　is　proposed.　A　subsequent　hydrothermal　treatment　of　alpha-Na2TiO3　regenerates　TiO2　photocatalysts　with　high　purity　(＞99.0%)　that　can　satisfy　commercial　requirements.　In　addition,　the　present　iron　element　contained　in　spent　SCR　catalystS　is　doped　into　regenerated　TiO2　photocatalysts,　resulting　in　providing　visible-light-driven　photocatalytic　activities.　The　regenerated　TiO2　photocatalysts　possess　superior　photocatalytic　degradation　capacities　for　dye　pollutants　and　can　be　used　to　efficiently　treat　wastewater.　This　work　introduces　a　promising　technology　for　the　cyclical　regeneration　of　titanium　from　spent　SCR　catalysts.