To explore the effect of the addition of poly(vinylidene fluorine) (PVDF) to a nanothermite system, an Al/MnO2/PVDF energetic nanocomposite was prepared using an electrospray method, Al/MnO2 nanothermite was prepared as a control group. Then, the energetic nanocomposite and nanothermite were tested and analyzed by XRD, FE-SEM and TG-DSC, and the reaction products were collected. The results show that energetic nanocomposite would have three obvious exothermic peaks in the range of room temperature to 800 °C with a total more than 1700 J g−1 heat release while the control experiment, Al/MnO2 nanothermite, could be found one exothermic peak with a 1100 J g−1 heat release. The residues are mainly MnAl2O4, MnF2 and AlF3 which indicates that Al/MnO2/PVDF energetic nanocomposite could make full use of manganese oxide. Finally, thermal analysis experiments were carried out under different heating rates to calculate the activation energy. The calculation results show that the addition of PVDF could significantly reduce the activation energy, which would help spark the thermite at comparatively low energy and temperature.