The general field of the invention is that of methods of three-dimensional graphical representation of a landing runway on a viewing screen of an onboard viewing system for aircraft, the said graphical representation being displayed in a synthetic view of an exterior landscape. The graphical representation according to the invention comprises a line disposed along the axis of the runway, the said line being a straight stripe inclined by an angle of between one and a few degrees with respect to the horizontal, the said line beginning at the runway threshold.