Abstract：Based on an investigation of the sedimentary characteristics of the Nanhuan diamictite (tillite) by means of grain size analysis and provenance discrimination of sandstone, the authors tentatively established the Nanhuan-Sinian sedimentary sequences in the southwestern margin of Tarim Basin. It is concluded that the Nanhuan diamictite (tillite) and the interglacial stage sediments were derived from recyclic orogenic zone, dissected island arc and transitional island arc. However, the sedimentary provenance discrimination of sandstone composition has made the authors believe that the Nanhuan-Sinian sediments in the southwestern margin of Tarim Basin have properties of the recyclic orogenic zone. This understanding is very important for restoring the prototype of the Tarim Basin.