Solution-phase hydrogen reduction (SpHR) was introduced into V₂O₃ preparation to overcome disadvantages of traditional reduction roasting, which include a long process, high energy consumption, and generation of pollution. The research mainly focuses on φ-pH diagrams and kinetics of SpHR. Thermodynamic analysis of φ-pH diagrams for the V-H₂O system demonstrates that V₂O₃ preparation via SpHR requires a high temperature, a high vanadium concentration, and sufficient hydrogen in acidic solution. Kinetic analyses show that the activation energy of V₂O₃ preparation via SpHR is 38.0679 kJ/mol, indicating that the reduction is controlled by a combination of interfacial chemical reaction and internal diffusion. Effects of H₂ partial pressure (slope K=0.05246) on the reaction rate is not as significant as the vanadium concentration (K=1.58872). V₂O₃ crystals with a purity of 99.59% and a vanadium precipitation rate of 99.83% were obtained under the following conditions: pH=5-6, c(V₂O₅)=0.5 mol/L, p(H₂)=4 MPa, m(PdCl₂)=10 mg, T=250 °C, and t=2.5 h.