To overcome the challenges in targeted oral delivery of postbiotics, this study developed a functional electrospun oral fiber membrane through a systematic three-step strategy. First, the optimal 1:2 mass ratio of octenylsuccinylated starch to polyvinyl alcohol was determined by analyzing rheology, conductivity, and fiber morphology to create a stable electrospinning matrix. Second, an oral-derived Lactobacillus plantarum postbiotic was identified as the optimal functional component based on antioxidant, antibacterial, and probiotic-promoting effects. Third, when the postbiotic loading reached 15 mg/mL, the membrane exhibited uniform fiber morphology (average diameter 386 nm), oral-compatible surface pH, and contour-adaptable mechanical performance, supported by stable hydrogen-bonding interactions. Functionally, the membrane demonstrated near-complete pathogenic bacteria inhibition, approximately 70 % increased beneficial bacteria proliferation, effective oxidative damage prevention with a 22 % improvement in cell viability, and marked anti-inflammatory effects. These findings provide a promising delivery strategy for oral microenvironment modulation, advancing functional food development for oral health.