Using poly(2,5-dihydroxy-1,4-phenylenepyridodiimidazole) (PIPD) as a matrix, PIPD nanofiber aerogels were prepared by peeling off the PIPD by the mixed acid, proton-consumption-induced gelation of PIPD nanofiber sol and freeze-drying, followed by high temperature treatment in an inert atmosphere. The morphology and structure of PIPD nanofiber aerogels were characterized. The results show that in the process of preparing PIPD nanofiber aerogels, the strong protic acid disrupts the crystal regions and orientation of the PIPD fibers, and the chemical structure of the PIPD does not change significantly. PIPD nanofiber aerogels have a honeycomb structure, low density (6.90~15.2 mg/cm3), high porosity (99.1~99.6%). When the PIPD fiber content (based on the total mass of MSA and TFA, the same below) is not higher than 1%, the PIPD nanofiber aerogels do not shrink significantly. High temperature treatment in an inert atmosphere makes PIPD nanofiber aerogels elastic. Horizontal and vertical combustion, the limiting oxygen index (LOI), and thermal conductivity tests show that PIPD nanofiber aerogels reach the non-flammable level (UL-94, V-0), LOI is as high as 49.2%, and the thermal conductivity is 0.052 W/(m·k) at 100 ℃. In addition, the introduction of Cu2+ coordination cross-linking network enhances the compressive stress of PIPD nanofiber aerogels, and the compressive stress of the enhanced aerogels are 15 times that of the original PIPD nanofiber aerogels.