The effect of coating agent ammonium perchlorate (AP) on the thermal reaction characteristics and ignition combustion characteristics of nano-aluminum powder (nAl) in CO2 were studied by thermal analysis techniques and visualized tube furnace. The decomposition process of AP is different because there are different heating rates between thermal analysis instrument and visualized tube furnace, so that the ignition combustion characteristics of nAl have a certain difference; At a slow heating rate, the ignition temperature of nAl coated with AP is higher than that of nAl. However, the product O2 which is produced by AP can promote the reaction of nAl, so the mass gain of nAl coated with AP is higher than that of nAl. Also, with the increase of the concentration of coating agent AP, the mass gain of nAl coated with AP increases. At a fast heating rate, the ignition temperature of nAl coated with AP is lower than that of nAl. Especially, for nAl coated with 10% and 15% AP, the ignition temperatures decrease by about 200℃ due to the decomposition of AP in rapid decomposition to have obvious effect on the ignition phenomenon of nAl.