Herein, we report a novel ammonia (NH3) sensor material with outstanding sensing performance based on freestanding polyaniline (PANI) coated inorganic silica (SiO2) nanofibers (SNF) membranes, which could work well at room temperature. SNF membranes were prepared by the combination of sol-gel, electrospinning and calcination methods It was realized per the results that the flexibility of SNF membranes could be considerably controlled by calcination temperature. SNF were diverted from flexible to brittle as the temperature increased from 600 degrees C to 1000 degrees C. In order to adapt to wearable gas senor demands, flexible SNF membranes obtained from heat-treated at 600 degrees C and 800 degrees C were used as templates for in-situ polymerization of aniline. The gas sensing behavior of PANI coated SNF of 10 ppm to 300 ppm NH3 were operated at room temperature. Gas sensing tests revealed that the SNF/PANI composite nanofibers had high response values. Additionally, the gas sensing abilities of PANI coated on SNF annealed at 800 degrees C was much higher than SNF treated at 600 degrees C. Moreover, the PANI coated SNF (annealed at 800 degrees C) could detect NH3 to 400 ppb, as well as showed excellent selectivity, repeatability and reversibility. The flexible SNF/PANI membranes were easy to prepare and it obtained ideal flexibility, which exhibited their potential for applying as wearable gas senor.