Abstract: Graphene, as a new type of reinforcement material, has a wide application prospect in strengthening the mechanical properties of metals. The indentation response of single crystal aluminum (Al) and aluminum coated by single or double-layer graphene (Gr/Al) was calculated by molecular dynamics method. The indentation properties of Al and Gr/Al under the spherical indenter were studied, and the indentation mechanical behaviors were analyzed to investigate the influence of Gr coating on Al matrix properties under indentation. The results show that the Gr coating can significantly enhance the bearing capacity of Al matrix, and improve the hardness and reduced elastic modulus of Al matrix. Through the analysis of deformation behavior, internal stress and dislocation expansion, it is found that there are two main reasons for Gr to improve the indentation performance of Al matrix: one is the increase of bearing area of Al matrix under the "lifting action" of Gr coating. The second is that Gr coating changes the dislocation expansion in Al matrix. By comparing the indentation properties of Al matrix under single and double Gr coating, it is found that increasing Gr layer number can improve the bearing capacity of the whole system, but reduce the critical depth of the system.