This paper presents a new security precaution measure for submarine fiber cables

i.e.embedding fiber grating hydrophones in the cable to monitor anchor dragging in the vicinity of the submarine cables

analyzes the traits of the acoustic sources and builds a acoustic field model on the basis of Taiwan Strait and simulates the acoustic Transmission Loss（TL）.The simulation results show that when these hydrophones are spaced 500 mapart

this method can be used to determine the location of the acoustic sources in the scope of about 1km along the submarine cables.