Nanocomposite gas transport and thermally stable membrane-based fluorinated polyimide/TiO2 nanoparticles were prepared via in situ sol-gel fabrication. PI/TiO2 nanocomposites containing 4, 8, and 12% TiO2 were successfully fabricated by in situ sol-gel fabrication. The obtained PI/TiO2 nanocomposites were characterized by Fourier transform infrared (FT-IR) spectroscopy, thermogravimetry analysis, X-ray powder diffraction, field emission-scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). Thermogravimetric analysis data indicated an increased thermal stability of the PI/TiO2 nanocomposites compared to the pure polymer. The results of gas permeation showed the permeability of ethylene and propylene increased in PI/TiO2 nanocomposites compared to the pure PI. The diffusion coefficients of prepared hybrid membranes were determined by the time lag method. The results showed an increase in the solubility coefficient and a decrease in the diffusion coefficient of gases while increasing the TiO2 nanoparticle mass fraction.