Abstract: For a high aspect ratio UAV at low altitude, the flows around both the full vehicle and the airborne magnetic gradient measuring probe on its wing-tip were numerically simulated, respectively. The calculation of the full vehicle obtained the influences of the wing-tip airborne magnetic gradient measuring probe on the full vehicle aerodynamic characteristics and its control and stability; the calculation of the wing-tip airborne magnetic gradient measuring probe implemented its optimization design of aerodynamic configuration, and the aerodynamic drag increment of the full vehicle decreased at the furthest on the premise of keeping the full vehicle control and stability. Results show that the aerodynamic drag increment of the full vehicle related to the airborne magnetic gradient measuring probe is controlled within 9% and the variation of pitching moment is within 5%. The full vehicle control and stability is scarcely influenced by the airborne magnetic gradient measuring probe, and its optimization design of aerodynamic configuration mainly meet the technique requirement of the safe flight of the high aspect ratio UAV at low altitude.