In this work, a series of cellulose/collagen hydrolysate (RC/CH) films were prepared in NaOH/urea aqueous solution via a simple, low-cost and green pathway. To overcome the disadvantages (brittleness, poor water resistance) of CH as biomaterials, CH was combined with regenerated cellulose (RC) film to construct RC/CH composite materials, leading to vast improvement of the water resistance of CH. Crosslinking with genipin further improved the mechanical properties of the RC/CH films in the wet state. Their structure and properties were characterized by elemental analysis, Fourier transform infra-red (FT-IR) spectra, ultraviolet-visible (UV-vis), scanning electron microscopy (SEM), amino acid analysis, tensile testing, cell adhesion and toxicity tests. The mechanical properties and water resistance of the crosslinked RC/CH films were significantly improved, which made collagen hydrolysate as biomaterial could be used at wet state. Moreover, the RC/CH films exhibited good biocompatibility by proliferation of COS7 cells on the surface, supporting cell adhesion and growth.