Polyoxometalates(POMs) have conducive properties such as controlled Br?nsted and Lewis acidity, high thermal stability, nontoxic nature, tunable solubility, and less corrosiveness. POMs have been extensively applied in catalytic organic reactions and have an exciting prospect for industrial applications. This review summarized recent progress in the application of POMs as acid catalysts for various organic reactions including C–C bond formation, C–N bond formation, C–O bond formation, heterocyclic synthesis reactions,cyanosilylation and hydrolysis reactions. Various POMs catalysts including heteropoly acids(HPAs) and cationic functionalized HPAs with Br?nsted acidity, HPAs supported on non-precious metal support with Br?nsted acidity(or both Br?nsted and Lewis acidity), transition metal substituted POMs with Lewis acidity were applied in above reactions. This review attempts to provide up-to-date information about POMs acid-catalyzed organic reactions and propose future prospects.