Abstract: The Qinling Orogenic Belt, situated between the South China Block and the North China Block, has undergone multi-stage evolution from the Paleozoic to the Early Mesozoic, comprehensively documenting the collisional orogenic processes between the South China and North China Blocks. However, key scientific issues regarding the early Paleozoic tectonic framework and the late Paleozoic evolution of oceanic basins in the Qinling Orogenic Belt remain controversial. The West Qinling region, as the western extension of the Qinling Orogenic Belt, serves as a critical window for studying its tectonic evolution. This study focuses on the Devonian, Carboniferous, and Permian strata exposed in the Zhaishang area of Min County, West Qinling, and conducts detrital zircon LA-ICP-MS U-Pb geochronological research to constrain the Paleozoic tectonic evolution and sedimentary processes of the Qinling Orogenic Belt. The U-Pb geochronological results reveal that the detrital zircons from the Devonian Shuanglanggou Formation of the Xihanshui Group yield a main age peak at 794 Ma, while the Lower Carboniferous Badu Formation shows a dominant peak at 818 Ma, and the Middle Member of the Lower Permian Shilidun Formation exhibits a primary peak at 443 Ma. Comparative analysis indicates that the detrital materials of the Devonian Shuanglanggou Formation and the Carboniferous Badu Formation share a common provenance, primarily derived from the South China Block, with both formations deposited in a rift basin setting. In contrast, the detrital materials of the Middle Member of the Permian Shilidun Formation are mainly sourced from the North Qinling Orogenic Belt, indicating a back-arc basin tectonic setting. This sedimentary-tectonic evolution provides critical constraints for the tectonic evolution of the Mianlue Ocean Basin, suggesting that the opening of the Mianlue Ocean occurred after the Early Carboniferous, while the closure of the Shangdan Ocean predated the Early Permian. These findings offer new geochronological constraints for regional tectonic evolution studies.