HfO₂ films were successfully prepared by low-cost and easy-to-operate liquid deposition method， and the surface appearance， composition， optical characteristics， and electrical properties of HfO₂ thin films generated by liquid deposition method were studied， as well as the reaction mechanism. The results revealed that the chemical composition of HfO₂ thin films generated by liquid deposition method was pure and the structure was dense and continuous. The transmittance of HfO₂ films after annealing at 500 ℃was greater than 92%； after making a plate capacitor with 40 nm hafnium oxide as the dielectric， the leakage current density at the voltage of 1 V was 3.56×10^-7 A/cm²； the capacitance value at the 1 MHz frequency was 1.05 nF， yielding a calculated permittivity of 18.9.The successful preparation of hafnium oxide thin film by liquid deposition could provide a low-cost and simple method for using hafnium oxide thin film as the passivation layer of Micro LED devices.