A polymer-iron oxide nanocomposite film has been successfully synthesized by using a microporous regenerated cellulose film as template and aqueous ferrous chloride a precursor. the nanocomposite film was investigated wit XRD, XPS, SEM, TEM, and VSM. The nanoparticles synthesized in situ were disk-shaped with a mean diameter of approximate to 24 and thickness of 2.5-3.5 nm. For the first time, the nanodisks were well aligned in the cellulose matrix to form an ordered multibilayer structure by the shrinkage of the hybrid film while drying. The nanocomposite film displayed anisotropic magnetic properties as a result of the alignment of magnetic nanodisks. This work provides a novel and facile method for template synthesis of nanoparticles and aligned nanocomposites.