Various preparation methods have been widely explored to improve the combustion performance of nanothermites in recent years. In this work, two kinds of Fe₂O₃-containing nanothermites were successfully prepared by in-situ ball milling method and conventional ultrasonic blending method respectively. The morphologies and performance of as-prepared products have been fully characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), contact angle tests, scanning electron microscopy (SEM), high-speed imaging experiments and infrared temperature measurement. The results show that the Fe₂O₃-doped nanothermites via in-situ ball milling method exhibit better performance than that made by ultrasonic blending method. The optimal nanothermites with 17% Fe₂O₃ doped amount possess the maximum mass gain percentage of 13.1% per 100 ℃. Compared with the products made by ultrasonic blending method, the heating voltage and initial combustion temperature of in-situ ball milled nanothermites decrease to 12 V and 600 ℃, respectively. In addition, the combustion flame of in-situ ball milled nanothermites is more stable and homogeneous than the corresponding one.