Hydrogel with anisotropic properties has promising potentials, while its fabrication is still challenging. In this work, chitosan fiber (CF) was designed to reinforce polyvinyl alcohol (PVA) hydrogel anisotropically. First, CF was pretreated in a weak acidic buffer to create rough surface as well as outwardstretched chitosan chain end segments, and then mixed with PVA in solution. A PVA/CFs composite hydrogel was thereafter prepared by casting the mixture with a pushing force followed by freeze-thawing cycles. The microstructure of the composite hydrogel was characterized by scanning electron microscopy, optical microscopy and Fourier transform infrared spectroscopy, and its mechanical properties at the directions parallel to and perpendicular to the casting force were measured. Our results indicate that the pre-treated CF can reinforce the PVA hydrogel effectively, especially along the casting force direction.