Gallium oxide (Ga2O3), as a new kind of ultra−wide band gap semiconductor material, is widely studied in many fields, such as power electronics, UV − blind photodetectors, solar cells and so on. Owing to the advantages of its excellent performance and broad application prospects in semiconductor technology, Ga2O3 materials have attracted extensive academic and technological attention. This review mainly focuses on introducing the main liquid−phase synthesis methods of Ga2O3 nanoparticles, such as direct–precipitation, chemical bath deposition, hydrothermal, solvothermal, and sol–gel method, including the characteristics in process and advantages and disadvantages of these methods. Then, the effects of reaction conditions, such as pH, capping agent, aging and calcination conditions, on the morphologies and sizes of the precursor and the final products were elucidated. Moreover, the applications of Ga2O3 particles in the fields of catalysis, gas sensors, and other devices in current research on Ga2O3 nanomaterials are discussed with the description of the basic working principle and influence factors. Display omitted •The synthesis methods and the applications of Ga2O3 particles are reviewed.•The effects of reaction conditions on the morphology and size of Ga2O3 particles and its precursor  are discussed.•The photoluminescence, photocatalytic and gas sensing performance of Ga2O3 particles are discussed.