Infrasonic waves(frequency ≤ 20 Hz) are generated during the formation and movement of debris flows, traveling in air with a speed far higher than that of the debris-flow movement. Infrasound monitoring and localization of infrasonic waves can serve as warning properties for debris-flows. Based on the characteristics of infrasonic signals, this study presents a three-point array of infrasound sensors as time-synchronous multiple sensors for acquiring signals. In the meantime, the signals are sorted by mutual correlation of signals to figure out their latency, and by means of array coordinating to locate the sound source to realize the monitoring and positioning of a debris-flows hazard. The method has been in situ tested and has been proven to be accurate in monitoring debris-flow occurrences and determining their positions, which is particularly effective for pre-event warning of debris-flow hazards. Infrasonic waves (frequency ≤ 20 Hz) are generated during the formation and movement of debris flows, traveling in air with a speed far higher than that of the debris-flow movement. Infrasound monitoring and localization of infrasonic waves can serve as warning properties for debris Based on the characteristics of infrasonic signals, this study presents a three-point array of infrasound sensors as time-synchronous multiple sensors for acquiring signals. In the meantime, the signals are sorted by mutual correlation of signals to figure out their latency , and by means of array coordinating to locate the sound source to realize the monitoring and positioning of a debris-flows hazard. The method has been in situ tested and has been proven to be accurate in monitoring debris-flow occurrences and determining their positions, which is particularly effective for pre-event warning of debris-flow hazards.