In the North Continental Shelf of the South China Sea on the background of dominance of terrigenous clastic sediments, around coral fringing and barrier reefs, there widely develop recent mixed sediments, which consist of reefoid carbonates and terrigenous clastics. Textures of these mixed sediments are dominant by arenaceous and arenaceous - rudaceous, and include same biogenic frameworks. Occurrence of both carbonate and ciliciclastic sources, active hydrodynamic regimes and alternate of dry and wet climates are main factors of forming mixed sediments ,besides , the flucture of sea levels also have an active influence on it.There are three patterns of mixed sedimentation: stochastic, facies alternate and stochastic - facies alternate. Mixed sediments always are sedimentary complex, consiste of alternate and repeat of diverse patterns of mixed sedimentation. Sedimentary Facies model of mixed sediments of recent reefoid carbonates and siliciclasstics is developed from the facies model of friging and barrier reefs. Based on the sedimentary facies and textures they may be subdivided into 5 mixed sediments: 1) reef foundamental mixed sedimentary rocks and reef framework mixed sedimentary rocks; 2) reef flat sand - gravel mixed sedimentary rocks; 3) reef back beach - dune gravel - sand mixed sediments; 4) reef back lagaonal sand mixed sediments and 5) fore - reef ( flank ) littoral sand mixed sediments. The distinguish indicates of reefoid carbonate and siliciclasstic mixed sediments are components, which both coral deblis and classtics cosist of 10 - 50 ％ and other biogenic fragments are no counted. Recent mixed sediments in the continental shelf of the South China Sea are a typical example, which may provide scientific basis for all-round research sedimentology of the South China Sea and for comparative sedimentological research.