A novel amino‐functionalized polystyrene copolymer (PS‐NH2) was designed and synthesized with styrene and 4‐vinylbenzyl amine. Additionally, an amino modified glass (G‐NH2) was obtained as a carrier. (PS‐NH2/pyrene)/G‐NH2 fluorescent nanofibrous membrane [named (PS‐NH2/pyrene)/G‐NH2] was designed and prepared via electrospinning technique to detect representative saturated nitroaromatic (NAC) explosive vapor. The (PS‐NH2/pyrene)/G‐NH2 showed highly fluorescence stability in ambient condition and further displayed a high quenching efficiency of 70.9% toward trinitrotoluene (TNT) vapor (∼10 ppb) with an exposure time of 150 s at room temperature. The abundance of amino groups could effectively adsorb NACs and the binding of electron‐deficient NACs to the amino groups on the (PS‐NH2/pyrene)/G‐NH2 surface led to the formation of charge‐transfer complexes. The quenching constant (KSV) to TNT was obtained to be 1.07 × 1011 mL/g in gaseous phase with a limit of detection up to 2.76 × 10−13g/mL. Importantly, the (PS‐NH2/pyrene)/G‐NH2 showed notable selectivity toward TNT and 2,4‐dinitrotoluene vapors. Straightforwardly, the colorimetric sensing performance can be visualized by naked eye with a color change for detecting of different vapor phase NACs explosives. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46708