The study of Mesozoic sedimentary facies and its environments of Southwestern Tarim Bssin will provide information to know collision events in south margins of Tarim block during Triassic to late Jurassic, and also continental deformation in mid-Asia during Cenozoic Era. On the basis of geological survey and geophysical data, Mesozoic sedimentary system and environment have been analyzed. The results indicate that original distribution of Mesozoic sediments was controlled by previous paleo-tomography of late Triassic. A few isolated fault-bounded sages, located along the West Kunlun Range, are the results of NWW-SEE normal faults of early Jurassic but not activity of Talas-Ferghana fault. Sedimentary facies are dominated by alluvial fan, braid river delta. From late early-Jurassic to middle Jurassic, lake, swamp and river were prevailing sedimentary environments. Meanwhile, a possible huge lake linked present Tarim, Tula and west Qaidam basins together. During late Jurassic, alluvial facies were evident again. Early Cretaceous alluvial fans and fan deltas were prevailing along West Kunlun Range. At late Cretaceous, resulting from transgression from west to east in Southwestern Tarim Basin, continental clasts decreased eastwardly, while marine facies took dominance.