Abstract: A preparation method for a nanocomposite fiber membrane material based on a bio-based liquefied formaldehyde resin is provided. A bio-based raw material is processed through a phenol/polyethylene glycol complex liquefaction process, followed by divalent alkali metal hydroxide high ortho-position induction synthesis resinification and modification with the polymer polyvinyl alcohol to create a spinnable precursor as PVA-BLF. Subsequently, a coaxial electrospinning device is utilized, where PVA-BLF serves as a core layer and a titanium dioxide dispersion is used as a shell layer, to fabricate a PVA-BLF/TiO2 nanocomposite fiber membrane material. The average diameter of the nanocomposite fiber membrane is 150-450 nm, and the specific surface area is 500-700 m2/g. The porosity exceeds 60%, and the fracture elongation ranges from 5.5% to 6.5%, demonstrating excellent filtration performance and excellent regeneration performance, which can be developed as adsorption materials for water and air purification.