This paper is the result of marine geological survey engineering.

Objective Quaternary sedimentary thickness can not only reflect the provenance and sedimentary characteristics, but also reflect the controlling effect of tectonic activity on the sedimentary process.

Methods Based on a large number of single channel and multi-channel seismic data and borehole verification, this paper completely compiles Quaternary thickness map of the South China Sea for the first time.

Results Sedimentary thickness of Quaternary in the South China Sea varies greatly, the thickest part exceeds 2000 m, and the thinnest part is close to 0.

Conclusions Depocenters along the western margin of the South China Sea are located in the Yinggehai, Zhongjiannan and Wan'an basins, indicating that the fault zone in the western margin remains active during Quaternary and controls the development of subsidence centers. The NE trending depocenters on the northwest continental slope of the South China Sea may indicate that the northwestern South China Sea has still been dominated by extension in Quaternary. Quaternary in Dongsha sea area has been almost completely denudated, suggesting that this area has been continuously uplifted and scoured by strong current since Quaternary. Therefore, the northern South China Sea shows a pattern of subsidence in the west and uplift in the east. The relatively thicker Quaternary in the Manila Trench along the eastern margin of the South China Sea is mainly a result of tectonic compression making sedimentary layers imbricate and thicken and abundant sediment supply from Taiwan Island and the Philippine Islands.