Abstract: The detection of non-rigid target and event is one of the important content of underwater security. Taklng the dredging leads to a short-term high concentration of sand and mud as an example, the non-rigid underwater target detection method based on acoustic sensor transceiver was explored. Based on the sedimentation of sand and mud and the model of acoustic propagation, the law of non-rigid target's shape, location change influence the sound propagation and energy structure were studied. Computer simulation and experiment on the sea both indicated that the shape and density parameters ware changed and while through the dumping area the ray energy and construction were influenced obviously. By detecting the relationship among receiving acoustic signal energy and the structure with the sedimentation of sand and mud can realize the underwater detection of invasion objective, which can provide support for further inversion, tracking and have certain research significance and reference value.