Photocatalytic　remediation　of　industrial　water　pollution　has　courted　intense　attention　lately　due　to　its　touted　green　approach.　In　this　respect,　Keggin-based　polyoxometalates　(POMs)　as　green　solid　acids　in　photocatalytic　reaction　possess　superior　qualities,　viz.　unique　photoinduced　charge-transfer　properties,　strong　photooxidative-photoreductive　ability,　high　chemical　and　thermal　stability,　and　so　forth.　Unfortunately,　it　suffers　from　a　large　bandgap　energy,　low　specific　surface　area,　low　recoverability,　and　scarce　utilization　in　narrow　absorption　range.　Therefore,　the　pollutant　degradation　performance　is　not　satisfactory.　Consequently,　multifarious　research　to　enhance　the　photocatalytic　performance　of　Keggin-based　POMs　were　reported,　viz.　via　novel　modifications　and　functionalizations　through　a　variety　of　materials,　inclusive　of,　inter　alia,　metal　oxides,　transition　metals,　noble　metals,　and　others.　In　order　to　advocate　this　emerging　technology,　current　review　work　provides　a　systematic　overview　on　recent　advancement,　initiated　from　the　strategized　synthetic　methods,　followed　by　hierarchical　enhancement　and　intensification　process,　at　the　same　time　emphasizes　on　the　fundamental　working　principles　of　Keggin-based　POM　nanocomposites.　By　reviewing　and　summarizing　the　efforts　adopted　global-wide,　this　review　is　ended　with　providing　useful　outlooks　for　future　studies.　It　is　also　anticipated　to　shed　light　on　producing　Keggin-based　POM　nanocomposites　with　breakthrough　visible-　and　solar-light-driven　photocatalytic　performance　against　recalcitrant　organic　waste.　©　2020　Elsevier　Ltd