The single-phase perovskite structure YFeO3 microcrystals were prepared by hydrothermal method, using Y2O3, HNO3 and Fe(NO3)3 as raw materials and KOH as mineralizer. The effects of reaction time, temperature and pH value of solution on the phase compositions, particle size and magnetic properties were studied. The results indicate that as the reaction time and temperature increasing, the purity of the products improve. Pure phase YFeO3 are obtained at a suitable range of pH value. As the solution pH value decreasing, the particle size become smaller, the distribution of particle size become narrower, and grain magnetization increases. The optimum condition is pH=9.5, 260 , 60 h. ©, 2015, Chinese Ceramic Society. All right reserved.