The western segment of boundary fracture between the Markit Slop and the Bachu Fault-Uplift in the western Tarim Basin was once called the Serikbuya fracture zone. Based on a systematic analyses of seismic profiles, the paper thought that the Serikbuya fracture zone included, actually, two faults with obviously different dissected depth, dipping and active age. The western sector of the fracture zone was still named the Serikbuya fault, which was a basement-involved fault, composed of a series of lower-order back-thrusts and became narrower southeastwards. The major Serikbuya fault dipped to the northeast and activated in Miocene, with some branch back-thrusts activating in Pliocene. The eastern sector of the fracture zone was renamed the Kangxi fault by the paper, which was a fault of superficial detachment. The Kangxi fault, dipped to the southwest and activated in the Caledonian movement, which rejuvenated in Pleistocene after a long-term stabilization. Regionally, the Serikbuya fault attached to the Bachu NNW-striking fracture system which created in Miocene and stretched northwards into the Kalpin area(the South Tianshan Cenozoic intracontinental orogen), while the Kangxi fault attached to the Tazhong(central Tarim) NW-striking fracture system which created in the Caledonian orogeny. The recent study demonstrated that the Central Tarim Lower Uplift was a multiple oil-gas accumulation play, so the new understanding for the former Serikbuya fracture zone might support a new thinking for oil-gas exploration in the Markit Slop. The obduction of the Bachu Fault-Uplift along the Serikbuya fault resulted in the Paleozoic and Eogene of the Markit Slop area deepend buried further, and the thick mudstone and siltstone of Pleistocene was a good capping bed for oil-gas. To analyse the role of Serikbuya fault both in early stage of petroleum accumulation and later stage of gas-filling adjustment, the oil-gas exploration in the Markit Slop area should have a new breakthrough in near future.