To study the feasibility of preparing functional packaging composite from disused filter paper pulp by mechanical means. Mechanical methods including grinding and homogenization were used to separate 2 types of cellulose nanofibers (CNFs) in different sizes from the untreated and acetic acid-pretreated disused filter paper pulp. The water suspension of well-dispersed CNFs was filtered and then oven-dried to prepare films. Two types of CNFs-reinforced Polyvinyl Alcohol (PVA) composites were prepared by impregnation method, and their mechanical properties and transmittance were tested. The FE-SEM images showed that the diameter of CNFs from untreated pulp was distributed in the range of 300～500 nm, while that from acetic acid-pretreated pulp was significantly reduced to 80～100 nm. Compared with PVA sheet, the tensile strength (90.45 MPa) and the light transmittance (81.3%) of the acetic acid-pretreated CNFs/PVA composites were respectively raised by 201% and decreased by 10.3%. The result revealed that the addition of CNFs enhanced the mechanical properties of PVA, and that acetic acid-pretreated CNFs had better effects, which could be used as high-strength and highly transparent packaging materials.