The invention discloses a method for estimating the air propagation delay of a direct wave, wherein an azimuth, an elevation angle and a total delay of a multipath wave reaching a receiving end are obtained through a receiving device; a departure angle of a reflected wave is obtained using a geometric relationship of wave reflection; a hypothetical point on a direct wave ray is selected as a transmitting end, and hereby the air propagation delay of the direct wave and the position of a reflection point of the reflected wave are calculated; the propagation delay and distance of the reflected wave are calculated according to the total delay of the direct wave and the reflected wave and the position of the hypothetical point. The invention can obtain the air propagation delay of the direct wave, thereby obtaining a propagation distance of the direct wave and fulfilling the requirements of ranging and positioning.