Abstract: Strength is a important factor to consider when designing high-performance composite materials. Inspired by the excellent mechanical properties and complex hierarchical structure of nacre, a nanocomposite was designed, in which the graphene layers were interlaced in the polymethyl methacrylate matrix. Coarse-grained molecular dynamics simulations were used to investigate the effect of various geometrical variations on the mechanical properties under tension loads, including the two-dimensional geometric shapes of graphene, the number of graphene layers, the interlayer distance of the graphene sheets and the overlap length of the graphene sheets. The simulation results show that the strengthening effects of different geometries of graphenes on composites are very different, among which, the rectangle and sawtooth shapes are close to each other and are stronger than the trapezoidal graphene. There is an optimal number of graphene layers to make the composite have the strongest overall mechanical properties. The mechanical properties of graphene can be improved by reducing the interlayer distance of the graphene sheets or increasing the overlap length of the graphene sheets. Overall, this paper systematically studies the influencing factors of graphene-reinforced polymer composites and reveals the influence rules and microscopic mechanisms of each factor. This study provides a useful guidance for the design of nanocompo-sites with targeted properties.