High-entropy amorphous thin film has characteristics of both high-entropy alloys and amorphous alloys, thus exhibiting many excellent properties, which have attracted increasing attention from scientific workers. The concept, classification, and development process are first briefly described. The preparation technologies are introduced with their respective characteristics. Then, the research progress of structural property, mechanical properties, thermal stability, and corrosion resistance, as well as corresponding mechanisms, are clarified in detail. Finally, the prospect of future development of high-entropy amorphous thin films in the potential application fields of diffusion barrier layer, corrosion protection coatings, magnetic films, and other suggested fields are presented.