In recent years, halide perovskite materials have been extensively studied by researchers due to their excellent optoelectronic characteristics. Unlike traditional semiconductors, halide perovskites possess unique ionic crystal structures, which makes it easier to perform facile composition engineering to tailor their physical and chemical properties. Ion exchange is a popular post-treatment strategy to achieve composition engineering in perovskites, and various ion exchange processes have been used to modify the structural and functional features of prefabricated perovskites to meet the requirements of desired applications. This review summarizes the recent progress in ion exchange of halide perovskites, including mechanisms, strategies, and studies on different ion exchange. Additionally, the applications of ion-exchanged perovskites in microfluidic sensors, light-emitting diodes (LEDs), lasers, and solar cells are presented. Lastly, we briefly discuss the challenges in ion exchange of perovskites and hope that ion exchange can provide a more refined and reliable method for the preparation of high-performance perovskites.