KH-GE/NR composite materials were prepared by mechanical mixing process with natural rubber and γ-methacryloxy propyl trimethoxyl silane (KH570) modified graphene (KH-GE). The structure of KH-GE was characterized by FT-IR, Raman spectroscopy, XRD and SEM. In addition, the microstructure, vulcanization characteristics, mechanical properties and electrical conductivity of KH-GE/NR composite materials were investigated. The results showed that graphene had been modified by KH570 successfully and the layer space of KH-GE increased, which was favorable for the KH-GE dispersion in natural rubber network. The mechanical properties of KH-GE/NR composite materials were enhanced by the introduction of KH-GE. When the dosage of the KH-GE was1.0 %, the tensile strength and the elongation at break of composite materials were 17.57Mpa and 645.48%, respectively. In comparison with the rubber without KH-GE, the tensile strength of composite materials was enhanced by 122% and the elongation at break was enhanced by 21%. The research also confirmed that the volume resistivity of KH-GE composite materials decreased approximately three orders of magnitude.