Polyoxometalates (POMs) are a unique class of molecular metal oxides with a tunable structure at the atomic level. They have demonstrated various potential applications in various fields. In particular, POMs have been widely used as catalysts, due to their facilely modified acid–base properties and redox potential through molecular designing. Normally, POMs can be utilized as both homogeneous and heterogeneous catalysts, where the former favors high activity, while the latter benefits facile separation of the catalysts. Faced with the requirement for sustainable development, significant effort has been made in the preparation of POM-based heterogeneous catalysts. This review focuses on the recent developments in heterogeneous strategies of POM-based catalysts and their applications in liquid organic reactions.