Abstract: By analyzing the differences between binaural recording and real listening, it was deduced that there were some unrevealed auditory localization clues, and the sound pressure distribution pattern at the entrance of ear canal was probably a clue. It was proved through the listening test that the unrevealed auditory localization clues really exist with the reduction to absurdity. And the effective frequency bands of unrevealed localization clues were induced and summed. The result of finite element simulation showed that the pressure distribution at the entrance of ear canal was non-uniform, and the pattern was related to the direction of sound source. And it was proved that the sound pressure distribution pattern at the entrance of the ear canal carries the sound source direction information and could be used as an unrevealed localization clue. The frequency bands in which the sound pressure distribution patterns were significant different between front and back sound source directions were roughly matched with the effective frequency bands of unrevealed localization clues obtained from the listening test. To some extent, it supported the hypothesis that the sound pressure distribution pattern could be a kind of unrevealed auditory localization clues.