The ground effect on low aspect ratio flying wing configuration aircraft is more pronounced compared to conventional aircraft, significantly impacting takeoff and landing characteristics. This study employs non-structured nested mesh technology to solve steady and unsteady Reynolds-Averaged Navier–Stokes (RANS) equations, conducting numerical simulations to investigate the aerodynamic characteristics of the ground effect on flying wing configuration aircraft. The static and dynamic aerodynamic force patterns were obtained and compared with flight test data. The results indicate that as the height above the ground decreases, the ground effect intensifies, showing a clear nonlinear change in aerodynamic characteristics when the height-to-chord ratio (h/c) is less than or equal to 1. The increments in aerodynamic forces from dynamic and static simulations follow the same trend with respect to height above the ground, but the dynamic simulations exhibit larger increments in pitching moment, particularly when h/c is less than 1. The consistency between the flight test increments and the simulation increments is good when h/c is greater than 1, but the simulation increments are larger when h/c is less than 1.