Objective The Carnian Pluvial Episode （CPE） was a critical climatic perturbation in the Late Triassic， marked by a pronounced transition to warmer and more humid conditions. These environmental changes sub-stantially facilitated the accumulation of fine-grained sediments and the enrichment of organic matter. This study aims to elucidate the sedimentary and geochemical responses of Chang 7 member of the Yanchang Formation in the Ordos Basin to the CPE， by examining thick successions of organic-rich black shales. Methods A multi-proxy analytical approach was employed using core samples from well ZK903. Biomarker compounds serve as the principal dataset， supported by analyses of organic carbon isotopes， trace element geochemistry， and clay mineral assemblages. These proxies were used to reconstruct the paleoclimatic conditions， redox environment， paleosalinity， and organic matter sources across Chang 7 member to Chang 8 member. On this basis， an organic matter enrichment model was developed to interpret the basin’s response to the CPE. Results In the Ordos Basin， the Chang 7₃ submember records a distinct lithological transition from sandstone to black shale， signaling intensified influence from the CPE and progressively increasing organic matter accumulation. Geochemical proxies， including Sr/Cu and Sr/Rb ratios， together with clay mineral data， indicate a climatic shift from arid-hot to warm-humid conditions. Redox-sensitive parameters such as V/Cr and U/Th， along with biomarker ratios （Pr/Ph and Ts/（Ts+Tm））， point to a significant reduction in bottom-water oxygen levels during this interval. Additionally， increased Sr/Ba ratios and a higher gammacerane index （GI） suggest elevated precipitation and lake-level rise， which led to enhanced water column stratification and diminished vertical mixing. These conditions promoted the development of a freshwater， anoxic environment conducive to the preservation of organic matter. Notably， elevated values of ∑C{}_{{\mathrm{21}}^{-}} /∑C{}_{{\mathrm{22}}^{+}} and C₂₇/C₂₉ （ααα）R ratios in the Chang 7₃ interval indicate a shift in the biotic community structure， with a dominance of lower aquatic organisms， particularly algae， as the primary contributors to the organic matter pool. Conclusions The CPE exerted a profound influence on the paleoclimate and depositional dynamics of the study area. Enhanced thermal and hydrological conditions， in conjunction with lake stratification， promoted the accumulation of fine-grained sediments and created favorable conditions for both primary productivity and the preservation of organic matter. These factors jointly facilitated the formation of organic-rich black shales （oil shales） in the Yanchang Formation， underscoring the role of global climatic events in shaping regional hydrocarbon potential.