This work provides a novel approach to improve the fouling resistance of PVDF membrane. An amphiphilic graft copolymer (PVDF-g-PACMO) having poly(vinylidene fluoride) (PVDF) backbones and polyacryloylmorpholine (PACMO) side chains was synthesized using the radical polymerization method, and then the copolymer was cast into a flat membrane via immersion phase inversion. The results indicate that the PACMO chain was successfully grafted onto PVDF main chains, and the grafting degree of PACMO in PVDF-g-PACMO copolymer increases with the increase of the monomer concentration in reaction solution. The structure and performance of as-prepared membranes were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), contact angle measurement, static protein adsorption, and filtration experiments. It is found that a higher grafting degree of PACMO endows the copolymer membrane with larger membrane surface micropores and a better hydrophilicity. The improved hydrophilicity provides the copolymer membrane with the resistance of protein adsorption to the membrane surface and a high flux recovery.