As a promising ultra-wide bandgap semiconductor material, gallium oxide (Ga2O3) is attracting an extensive attention of researchers due to its feasible growth process, appropriate bandgap of 4.4-5.3 eV allowing for deep-ultraviolet (deep-UV) detection, good physical and chemical stability, high breakdown field strength and electron mobility, etc. Different from the strict processes for controllable crystalline Ga2O3 (usually refer to stable monoclinic β-Ga2O3), amorphous Ga2O3 (a-Ga2O3) film can be prepared uniformly at low temperature on a large-area deposition substrate, suggesting great advantages such as low manufacturing cost and excellent flexibility, dispensing with high-temperature and high vacuum techniques. Thus, a-Ga2O3 extremely facilitates important applications in various applied fields. Therefore, in this concise review, we summarized several major deposition methods for a-Ga2O3 films, of which the characteristics were discussed. Additionally, potential methods to optimize the film properties were proposed by right of the inspiration from some recent studies. Subsequently, the applications of a-Ga2O3 thin films, e.g., in photodetectors, resistive random access memories (RRAMs) and gas sensors, were represented with a fruitful discussion of their structures and operating mechanisms.