Based on a great deal of geological and geophysical data including ODP borehole data in the South China Sea (SCS), the figures of sediment pattern were developed and the mass volume was calculated both of the whole basin and during each stage of E₃, N¹₁, N²₁, N³₁, N₂, Q. Above the pre-Oligocene base, the sediment volume of SCS was 7.01×10⁶ km³ and the mass was 1.44×10¹⁶ t, and the average sediment rate was 6.22 cm/ka and accumulation rate was 12.8 g/cm²/ka since Oligocene. Most of the sediment deposited on the continent shelf and slope, while only 5% of total mass deposited in the Center Basin. The sediment basin, developed in the continent shelf and slope, occupied 34% of the whole area of SCS given the thickness contour 2000 m as the boundary, but more than 82% of total amount mass deposited in these basin, showing that sediment basin was the major part of sedimentary process in SCS. The sediment rates were the highest and the mass volume was the largest in SCS during Oligocene, which was quite different from the evolution of global sediment rates, and it can be concluded that the deposition of marginal seas is controlled by the local tectonic movement firstly.