Based on core facies sequence, sedimentary microfacies, seismic facies and logging facies, this study recognized three types of parasequence developed within oilbearing sandstone of top LowerKepingtage Formation in the western margin of the Manjiaer Depression of Tarim Basin during the Ordovician. 1) Grain changes from coarse and medium grain at the bottom, finegrained in the lower middle to coarse grain in the upper middle reflects a sedimentary parasequence from a shallow transgressive sedimentation, ingression mudstone to littoral deposition, in which oilbearing section in Yangwu 2 well is located at the depth of 5460~5468 m; 2) Graduallycoarsened sedimentary sequences from offshore mudstone, shoreface and foreshore environments, with the top section influenced by storm, belong to the parasequence, and oilbearing section was found to be at the depth of 6503~6512 m. 3) Parasequence depositing in sublittoral and intralittoral zones has fine grains upwards, in which oilbearing section of Jinan No. 1 well was developed at the depth of 5465~5486 m. Oilbearing sandstone of the first type of parasequence (Yangwu No. 2 well) is earlier that that of the third type, while Oilbearing sandstones of the second type Grain (Yuenan No.2 and Hade No. 13 well) and of the third type (Jinan No. 3 well) is later than the fourth parasquence. The firsttype parasequence developed at the top of Yangwo No. 2 well at the early stage is favorable zone to development of reservoirs layers. To the north of the well and close to the ower Kepingtage Formation, shoreoff reservoirs depositing at stage of the thirdtype parasequence is also favorable position for oilgas accumulation.