Perchlorates with the strong oxidizing capability and gas generating have been widely used in energetic formulations， such as solid propellants and pyrotechnics. In order to study the effect of perchlorates on reactivity of Al-MnO₂ nanothermite， the potassium perchlorate （KClO₄） and ammonium perchlorate （NH₄ClO₄） have been used as typical additives to prepare KClO₄-Al-MnO₂ and NH₄ClO₄-Al-MnO₂ nanocomposites by electrospray method. The samples were characterized by field emission scanning electron microscope （FE-SEM）， simultaneous thermal analysis （TG-DSC）， X-ray diffraction （XRD） and combustion tests. The results showed that the Al nanoparticles and MnO₂ nanorods are distributed evenly on the surface of perchlorates substrates. All of perchlorates in nanothermite system would decompose exothermically before the thermite reaction. The mass fractions of nanothermite components has to be replaced by KClO₄ and NH₄ClO₄， which leads to the delayed thermite reaction by 21 ℃ and 31 ℃ according to the thermal analysis. The phase analysis of the collected reaction residues after TG-DSC tests indicates that the main product of KClO₄-Al-MnO₂ nanocomposite is Mn₃O₄， whereas it is MnO for NH₄ClO₄-Al-MnO₂， which means that NH₄ClO₄ can better improve the utilization of O elements in MnO₂. In the case of reaction kinetics， both perchlorates greatly reduced the activation energy of thermite reaction by more than 35%. The ignition and combustion experiments were carried out using a fast heating wire. The addition of perchlorates can significantly increase the burning rate， but they can also reduce the size and brightness of the flame. This work provides a new understanding for design and development of the additive selection for nanothermite formulations.