Abstract: The abyssal trench is an important and special funnel-shaped landform area in the deep sea, which has been regarded as the “desert” for many years. Recent studies have revealed that the abyssal trench area is not only a sink of deep-sea sediments, but also has an active abyssal ecosystem, and an important site for the burial of deep-sea organic carbon. This article conducts experimental analysis on sediment short column samples collected from the axis of the New Britain Trench. The distribution of natural radioactive nuclides (²¹⁰Pb_ex, ²²⁶Ra, ²³⁸U, ²³²Th, and ⁴⁰K) and environmental magnetism parameters in the column samples are used to determine the source of the sediments, and TOC is combined with δ¹³C parameter to further identify the source of organic matters in sediments and to calculate the contribution ratio. The research results indicate that the sources of sediment in the axis of the New British Trench are mainly controlled by three sources: terrestrial, volcanic, and carbonate caves. Secondly, the top samples are influenced to some extent by human activities.