Abstract: Core-shell structural γ-Fe₂O₃/SiO₂ nano composite particles were prepared via hydrolysis and condensation by sol-gel method using TEOS as silica precursor. Orthogonal design and single factor experiment were utilized to study effect of seven factors on the synthesis of nano composite particles, such as the dosage of γ-Fe₂O₃, Ammonia water, TEOS, the ratio of alcohol to water, reaction time, reaction temperature and stirring speed. The synthesized products were characterized by transmission electron microscope(TEM), X-ray diffraction(XRD), infrared spectrometer(FTIR), differential scanning calorimetry(DSC)and particle size analyzer. The results showed that the dosage of TEOS had the most influence on the synthesis of core-shell structural γ-Fe₂O₃/SiO₂ nanocomposite particles. The optimum conditions were as follows:γ-Fe₂O₃ 0.06 g, TEOS 0.5 mL, ammonia 2 mL, the ratio of alcohol to water 5:1, reaction time 8 h, reaction temperature 30 ℃ and stirring speed 150 r/min. Compared core-shell structural γ-Fe₂O₃/SiO₂ with γ-Fe₂O₃, the average particle size was reduced by 34.1% and particle size distribution was more uniform, with good dispersion.