A new type of nanothermite composed of n-Al (metal fuel) and FeF3 (oxidizer) was investigated in this paper. The thermal behavior and combustion properties of the n-Al/FeF3 nanothermite were compared with that of nAl/Fe2O3 nanothermite by TG/DSC-MS, XRD, SEM and high-speed camera. The results showed that the decomposition of FeF3 begins at 300 degrees C and releases free F ions. The F ions react with Al2O3 shell covered on the surface of aluminum. The start and exothermic peak temperatures of the major reaction of n-Al/FeF3 are at 415 degrees C and 520 degrees C respectively, which are 95 degrees C and 34 degrees C lower than those of n-Al/Fe2O3. Furthermore, the FeF3 will be reduced to Fe completely at 700 degrees C. However, the Fe2O3 could only be converted to Fe3O4. It demonstrates that the reaction of n-Al/FeF3 is completely, but only a part of n-Al/Fe2O3 reacts at 700 degrees C. The n-Al/FeF3 has larger, brighter flame and shorter burning time than n-Al/Fe2O3 in open air.