The Permian Pingdiquan Formation is an important exploration stratum in the eastern uplift area of Junggar Basin. On the west side of the uplift area，Huoshaoshan Oilfield with abundant petroleum geological reserves has been found in Zhangbei fault-fold belt，while in Shiqiantan Sag on the east side，only oil and gas shows are observed，with an unclear future direction for favorable exploration. Through systematic analysis of seismic survey，outcrops，as well as drilling and logging data，the sequence stratigraphic units of Pingdiquan Formation were divided，and the sedimentary characteristics within the sequence stratigraphic framework were clarified. In addition，a sequence sedimentary filling model was constructed. Accordingly，the petroleum geological characteristics in Shiqiantan Sag were analyzed. The results indicate that Pingdiquan Formation in Shiqiantan Sag is divided into two third-order sequences from bottom to top. Sequence1 developed the lowstand system tract，the transgressive system tract and the highstand system tract，while Sequence 2 developed the lowstand system tract and the transgressive system tract，without the highstand system tract. During the sedimentary period of Sequence1，deltas and fan deltas developed in the north and south of Shiqiantan Sag，and the dark shale of semi-deepdeep lacustrine facies developed in the transgressive system tract，becoming a set of good source rocks. In the sedimentary period of Sequence 2，fan deltas and shore-shallow lacustrine sediment developed in Shiqiantan Sag from north to south. In Sequence 1，the fan delta front and grey flat in the transgressive system tract and the fan delta front，delta front，and grey flat in the highstand system tract are adjacent to source rocks，which are the most favorable sedimentary facies belts in the study area. The progradational sandbody at the delta front of the highstand system tract represents a favorable exploration direction for lithologic reservoirs.