The coupling relationship between strike-slip faults and ancient karst processes has not been well studied. This paper examines strike-slip fault TH12518 in the Tahe Oilfield aiming to clarify the coupling relationship between the fault’s internal structure and ancient landform and water systems, by studying the characteristics of spatiotemporal structural superposition and transformation in the Ordovician Yijianfang Formation as well as karst activities during different tectonic phases. TH12518 experienced multistructural superposition under multistage tectonic activities, yielding five structural styles: pull-apart + translational + pull-apart (I); split + translational + translational (II); translational + compressive + pull-apart (III); translational + compressive + translational (IV); reverse thrust + overthrust (V). Stuctural styles I, II mainly occur in the middle Calendonian period, while structural supperposition between various structrual styles (I-V) occurs in the late Caledonian and early Haixi periods, under “bending effect.” There are significant differences in karst landforms between different karst periods. The water systems are underdeveloped during episode I of the middle Caledonian; whilst during episodes II, III the northern part uplifts to form a quasi karst plain while the southern karst slope area develops near N-S trending surface water systems and underground rivers. In the late Caledonian, multiple sets of water systems are developed in the karst slope area, forming a new NE-E trending underground river and surface water system along the fault. And in the early Haixi, large meandering rivers are developed on karst slopes. The karst processes in the Yijianfang Formation differ between different karst periods, regions, and segmentation styles. Episode I of the middle Caledonian develops exposed karst, overall, with infiltration and dissolution along the fault and strong dissolution in the N-NE trending fault segments; episodes II, III develop exposed karst in the north and semi-open overpressure karst in the south; with the segmented dissolution further enhanced, a sinking, buried fault-controlled karst is also developed in episode II. In the late Caledonian, exposed karst, semi-open overpressure karst, and sinking, buried fault-controlled karst are developed. The north, controlled by the karst baseline, exhibits limited downward karst process at the Cambrian top-dolomite interface; the south, not controlled by the reference plane, shows extensive downward dissolution at least to the top of the Cambrian Avatag Formation. Vertically, the karst fissures and caves are clearly layered. Whilst in the early Haixi, semi-open overpressure karst is developed, with weak karstification except for the bending effect and segmentation. This study provides a geological basis for large-scale karst development in the region.