Abstract: The modified graphene/polyvinyl chloride (KH-GE/PVC) composites were prepared by melting mixing of polyvinyl chloride and modified graphene. The GE was modified with different contents of silane coupling agent γ-methacryloxy propyl trimethoxy silane(KH570), the changes of graphene structure before and after modification were characterized by FTIR, Raman, XRD, TEM and SEM. And the mechanical properties, electrical conductivity and stability of KH-GE/PVC composites were also investigated. The results show that the layer spacing of KH-GE composite is larger whenW(GE:KH570) mass ratio (the total amount is 100) is 1:2. With the increase of KH-GE content, the mechanical properties of KH-GE/PVC composites are significantly improved. When the content of KH-GE is 1.5wt%, the tensile strength and elongation at break of the composite are 23.98 MPa and 226.78%, respectively, which are 51.1% and 65.73% higher than the composite without KH-GE. Comparing with pure PVC, the corresponding 50% thermal weight loss(T_50%) and 90% thermal weight loss(T_90%) increase from 289.81℃ to 298.51℃ and 486.01℃ to 596.53℃ when the content of KH-GE is 1.5wt%. It indicates that the thermal stability of the films are improved and the conductivity of the composites are also enhanced.