•A novel polyimide/functionalized graphene composite matrix with double bond (GPI/AMG) was synthesized.•Cross-linked nanocomposite films based on GPI/AMG were prepared by using UV-curing technology.•The interaction between AMG and GPI matrix and the cross-linked structure improved the performance of the UV-cured films. Polyimide/amino-modified reduced graphene oxide (PI/AMG) composite matrix were synthesized through the condensation reaction of 4,4'-diaminodiphenyl ether, 3,5-diaminobenzoic acid, diphthalic anhydride, and AMG. Subsequently, the double bonds were incorporated into the matrix through the reaction of glycidyl methacrylate (epoxide group) and the carboxyl group on PI/AMG. UV-cured composite films were then prepared and performance was evaluated. The results revealed that the tensile strength and elongation at break could reach a maximum of 108.7 MPa and 46.4%, which represented increases of 102.8% and 354.9%, respectively, compared with the GPI/AMG0% film. The water absorption decreased from 0.64% to 0.27%. And their surface resistivity reached 106–109 Ω, an increase of approximately eight orders of magnitude.