Polypropylene nonwoven fabrics are treated by He atmospheric pressure glow discharge plasma. After plasma treatment, weight loss (%), surface properties (wettability, morphology, and chemical composition changes), tensile strength, low-stress mechanical properties, and air permeability of the fabrics are examined. Scanning electron microscopy analysis shows significant surface morphology changes in plasma-treated polypropylene fiber surfaces, corresponding to reductions in fabric weight. X-ray photoelectron spectroscopy analysis reveals that surface oxidation by the formation of hydrophilic groups enhances the surface wettability of the fabrics. Surface morphology changes with plasma treatment increase fiber-to-fiber friction, playing an important role in enhancing their tensile strength, low-stress mechanical properties, and air permeability.