Abstract: Abstract：The outcrops of Keping area in Tarim basin,where the lower Silurian depositional sequence is continuous and perfectly exposed, constitute a preferable study area for marine clastic deposition. However, depositional system types of the lower Silurian sediments deserve further discussion. Based on detailed outcrop observation and laboratory tests, the authors analyzed the lower Silurian depositional system types and their characteristics in Keping area. As a result, deltas and clastic coast systems composed of tidal flat and offshore were detected, and river-dominated deltas and tide-influenced deltas were recognized from the Lower Silurian strata in Keping area. Large scale river-dominated delta systems are developed in Kepingtage Formation, whereas tide-influenced delta systems and tidal flat systems are developed in Tataertage Formation. On such a basis, the depositional characteristics and differences of various depositional systems are studied and compared with each other.