The segregated graphene oxide(GO)/ultra-high-molecular-weight polyethylene (UHMWPE) composite films with various interfacial adhesion property were prepared by mechanical blending method from UHMWPE, GO, dodecyl amine (DA) functionalized graphene oxide(DA-GO) or uniform DA-GO/high density polyethylene (DA-GO/ HDPE) powder. The results of XRD and XPS indicated that DA chain was successfully grafted onto GO sheets via a chemical method, which enhanced the interfacial adhesion between UHMWPE particles and GO sheets. The characterizations of POM and SEM proved that good segregated structure was only obtained in DA-GO/UHMWPE or DA-GO/HDPE/UHMWPE composite. Strong interfacial adhesion between fillers and matrix exhibits positive effect on gas barrier property. Compared to the GO/UHMWPE composite film, dramatic decrease in O-2 permeability coefficient by 42.2 and 48.1%, from 15.4 x 10(-14) to 8.9 x 10(-14) and 8.0 x 10(-14) cm(3) cm cm(-2) s(-1) Pa-1, is achieved upon the addition of only 0.5 wt% fillers, respectively. The DSC results demonstrated that the enhanced gas barrier performance was ascribed to the strong interfacial adhesion between DA-GO/ HDPE and UHWMPE matrix, rather than the crystallinity of UHWMPE matrix. Additionally, the decrease in UHMWPE particle size might be conducive to improving the gas barrier property of composite films due to the formation of more isolation layers perpendicular to the film plane.