Abstract: With the continuous development of high-power laser technology, magneto-optical isolators have been widely used, which has promoted the development of magneto-optical materials, especially magneto-optical crystals, which are the key components of magneto-optical isolators. Fluoride magneto-optical crystals have the advantages of weak thermo-optical effect and high Verdet constant, and are regarded as ideal candidates for magneto-optical isolators in high-power laser systems. The characteristics and research progress fluoride magneto-optical crystals are introduced, and the future of these crystals is prospected.