Abstract: The performance of lithium-ion battery prefabricated membranes has an important influence on the performance of the separators. Functionalized polypropylene (PPOH) with hydroxyl contents (mole fractions, x_OH) of 0.5%, 1.2%, 3.0%, and 6.2% was successfully prepared via the copolymerization reaction of 10-undecen-1-ol with propylene. PPOH at different hydroxyl contents was melt-blended with polypropylene (PP) to investigate the effect of hydroxyl content on the properties of the prefabricated blend membrane.The chemical structure of PPOH was characterized by proton nuclear magnetic resonance (¹H-NMR) and Fourier transform infrared spectroscopy (FT-IR). The hydrophilicity, mechanical properties, and surface morphology of the prefabricated blend membranes were evaluated. The results indicate that with the increasing of hydroxyl content in PPOH, the hydrophilicity of the prefabricated blend membrane improves. However, excessively high hydroxyl content leads to enhanced incompatibility between the PPOH and PP phases, resulting in a reduction in mechanical properties. When x_OH is 1.2%, the blended membrane exhibits a tensile strength of 36.4 MPa, an elongation at break of 269.6%, a water contact angle of 92.7°, and a crystallinity of 50.4%. This study provides a guideline for separator preparation and a novel strategy for the hydrophilic modification of lithium-ion battery separators.