The invention relates to a channel leakage detector and method based on distributed optical fiber acoustic sensing technique, which comprises an optical system (1), a distributed optical fiber sensing system (2), and a detecting system (3). Wherein, the optical system comprises a board band continuous light resource A1, and an optical circulator A2; the distributed optical sensing system comprises the first coupler A3, the delay coil B4, and a reflective mirror A5l; the detecting system comprises an optical-electric converter A6, a demodulate system A7, a A/D converter A8, and a computer A9; the board band continuous light resource via the optical circulator is connected to the Port1 interface of the first coupler A3, whose Port2 and Port3 are connected with delay coil; the Port4 of first coupler via sensing optical fiber is connected to the reflective mirror; and the optical circulator is connected to the optical-electric converter of detecting system, while said system can detect any leakage signal at any time. |