A novel mussel-inspired sticky catechol-functionalized poly (ethylene glycol) (Cate-PEG) was synthesized and deployed as an additive to modify the hydrophobic poly (vinylidene fluoride) (PVDF) ultrafiltration (UF) membrane for reducing the leakage of poly (ethylene glycol) (PEG) from membrane matrix towards practical water treatment applications. By the interesting surface segregation, the sticky Cate-PEG polymer could migrate from matrix onto the membrane surface and internal pores, endowing the modified membrane with excellent hydrophilicity. In addition, the PVDF/Cate-PEG UF membrane exhibited a high water flux, good BSA rejection and a satisfactory antifouling performance after the BSA solution cycling tests. Most importantly, a wonderful stability of Cate-PEG in membrane matrix was discovered by the XPS analysis in the incubation treatment with hot water due to the strong sticky property of catechol structure in Cate-PEG. Therefore, the new sticky material has great potential not only for membrane surface modification but also for multifunctional manipulations of materials for diverse applications.