Abstract: Upper Triassic Xujiahe Formationis the major oil and gas exploration reservoir in southern Sichuan. Through analyzing the detrital components and heavy mineral, the several provenances have been existed in the Xujiahe Formation of southern Sichuan, inluding LongmenMoutain, Kangdian old land, Xuefeng ancient land and Qianzhong ancient land. LongmenMoutain provenance mainly affects the northwest part of this studying area, providing magmatic debris and metamorphic debris, and developing a NW-SE direction (short-axis) delta sedimentary system. The clastic rocks are occurred in the north and southeast parts of this studying area, including mudstone debris, silt debris and metamorphic debris, which are mainly sourced from Xuefeng ancient land with the development of a SE-NW direction (long-axis) delta sedimentary system. The southwest and south parts of study area are controlled by Kangdian ancient land and Qianzhong ancient land, which are supported by the evidences of the heavy minerals study.