Abstract: The ocean floor is rich in rare earth mineral resources, but how to get the distribution of these resources in the deep sea becomes the key to the next step in exploitation and utilization.This article focuses on the method and effect of Japan's exploration of REY-rich soft mud using SBP (sub-bottom profiling analysis) near South Bird Reef.The profile of the shallow stratigraphic section of the survey is introduced.The three phonograms of non-penetrating(O), transparent(T) and stratified(L) can be obtained by the echo diagram.The corresponding acoustic characteristics correspond to different submarine topographic features and the sedimentary core samples.It is concluded that T-type corresponds to REY-rich soft mud and L-phase represents non-REY-rich semi-oceanic sediments.Thus, according to the distribution of the phonogram, it is concluded that REY-rich slime is mainly distributed in the southern and southeastern seabed of the Minamitorishima EEZ, which is the target district in the future marine REE exploration.Nowadays, SBP should be a benefitial contribution and an applied innovation for marine rare earth exploring in the world.