Abstract: In order to clarify the influence of graphene nanosheet（GNSs） orientation angle on the mechanical properties and plastic deformation mechanism of GNSs/Mg composites, a molecular dynamics method based on the embedding of atomic potential, a single crystal magnesium matrix was established by lammps software, and GNSs with same thickness and same size were evenly embedded at different angles（0°, 30°, 60°, 90°） at medium distances of single crystal magnesium, and four GNSs/Mg composites were established for uniaxial compression simulation, and the stress-strain, atomic trajectories and other data were analyzed. The results show that the uniformly distributed GNSs play the role of diffusion strengthening,Orowan mechanism and load transfer in the composite, and the mechanical properties of GNSs/Mg are greatly improved, and when the orientation angle of GNSs is 0°, that is, the vertical compression direction, the mechanical properties and deformation resistance of the composites are greatly improved, and the Young’s modulus and yield stress reach 110.5 GPa and 9.16 GPa, respectively. The orientation angle of GNSs has no significant effect on the plastic deformation process of composites, and the number of lattice structures tends to be consistent, and the plastic deformation mechanisms are mainly atomic phase transition, dislocation nucleation and dislocation slip.