The CaO@ (Sr2Fe2O5-Fe2O3) magnetic catalyst was carried out by the co-precipitated method. Comparing pure CaO, the modified CaO acted better on the synthesis of biodiesel with soybean oil and methanol as raw material. After further reused for 5 times, the yield of biodiesel could still reach 89.0% at the optimal conditions (12:1 methanol to oil molar ratio, 0.5 wt.% catalyst concentration, 70 degrees C reaction temperature, 2 h reaction time), which indicated that the CaO@ (Sr2Fe2O5-Fe2O3) catalyst was stable. The preparation of CaO@ (Sr2Fe2O5-Fe2O3) heterogeneous catalyst would provide more choices for industrial application. (C) 2016 Elsevier Ltd. All rights reserved.