Abstract: The sound field frequency-range interference patterns in deep water are discussed based on ray theory when the source and the receiver are near the sea surface. In the shadow zone, the sound intensity periodical structure is caused by the interference among the bottom-reflected wave, the bottom-reflected surface-reflected wave, the surface-reflected bottom-reflected wave and the surface-reflected bottom-reflected surface-reflected wave. The sound intensity changes according to frequency with two cycles, which increase with the increase of the propagation range, and decrease with the increase of the depth of the source and receiver separately. As a result, the range and depth of the broadband sound source can be extracted from the interference cycles of the sound intensity using a single hydrophone, which is validated by simulation analysis. The sound field interference patterns caused by sea-surface broadband noise sources in the shadow zone have been observed in a deep-sea experiment in the South China Sea. The availability of the deep-sea sound field interference structure in the passive source localization is verified by experimental data analysis results. Compared with conventional passive source localization methods, this method doesn't need broadband guide sources, precise seaflooracoustic parameters and large scale computing of replica fields.