In this paper, the electrochemical synthesis method was used to prepare γ-Bi2O3. Ultrafine Bi metal powder was first synthesized by electrochemical method at room temperature in a single cell .The anode comprised the sacrificial metal Bi; the cathode was Pt; the NaOH solution was used as the electrolyte. The ultrafine Bi metal powder had a special chemical reactivity. Then γ-Bi2O3 was prepared by the reaction of ultrafine Bi and NaOH solution. The effect of the concentration of NaOH solution, reaction temperature and additive were studied. The principle of the reaction was discussed. The component of the product was determined by atomic emission spectrometry and EDTA titration analysis. XRD, SEM ,TEM and DTA were employed for the characterization of the obtained products.