Hydrochloric acid pickling wastewater was pretreated by iron as deoxidizer and sodium chlorate as ox- idant. The precursor of zinc ferrite (ZnFe₂O₄) was prepared by coprecipitation method, and the zinc ferrite crys- tals were obtained by calcination at different temperatures. Zinc ferrite was used as catalyst in photodegradation of Rhodamine B. The results showed that the nano-zinc ferrite had better crystalline form and dispersibility by calcination under high temperature with uniform particle size obtained by calcination at the same temperature. In the photocatalytic treatment of Rhodamine B simulated wastewater, zinc ferrite had a higher catalytic effect at 0.2 g/L. Its catalytic efficiency was only reduced about 10% after four repeated experiments, indicating that zinc ferrite still has great stability.