As a new type of oxide system, high entropy oxides have broken the traditional design concept of doped oxide and are composed of five or more kinds of oxides in equal or nearly equal mole. Because of its simple structure and excellent performance, it has been widely concerned by researchers at home and abroad in recent years. High-entropy oxides tend to form solid solution structures such as rock-salt type, calcium fluoride type, spinel type or perovskite due to the disordered arrangement of multiple principal elements. Therefore, it shows various excellent performances, especially in energy storage materials and magnetic materials, which has a very broad application prospect. However, there are few research on high-entropy oxides, especially on the application of high-entropy oxides. This work first introduced the preparation methods of high-entropy oxides at home and abroad, mainly including solid state reaction method, pyrolysis method, co-precipitation method, hydro-thermal synthesis method and solution combustion synthesis method. In addition, the advantages and disadvantages of each method were also discussed, and these offered a wide range of flexible approaches for different type of applications of high-entropy oxides. Then the applications of high-entropy oxides as Li-ion electrode materials, giant dielectric materials, magnetic materials and catalytic materials were summarized. At last, the problems of high-entropy oxides in the present research were pointed out, and the future developments were also prospected. This review had certain guiding significance for the expansion of the application of high-entropy oxides subjects in the future direction.