Abstract: The division of Quaternary strata in the Yangtze River alluvial plain provides a fundamental basis for reconstructing the evolutionary processes of the Quaternary environment and serves as an effective standard for calibrating reflection layers and interpreting shallow seismic profiles. It also underpins studies of urban active faults and seismic hazard assessment. In this study, we analyzed the lithology, color, material composition, sedimentary structures, and other characteristics of Quaternary deposits with a total thickness of 78 m from the BZK1 core at Liqiao Village, Xilian Town, Yi’an District, Tongling City. Based on detailed stratigraphic subdivision, a Quaternary age framework for the BZK1 core was established using a combination of dating techniques, including optically stimulated luminescence and electron spin resonance. Grain-size analysis was further applied to investigate the regional sedimentary environment. The BZK1 core reveals, from bottom to top, the sedimentary sequences of early Middle Pleistocene alluvial facies (56.7–76.2 m), late Pleistocene fluvial facies (35.0–56.7 m), and Holocene floodplain facies (0–35.0 m), but lacks deposits from the Early Pleistocene and the middle to late Middle Pleistocene. The establishment of the Quaternary stratigraphic framework for the BZK1 borehole provides a reliable geological reference for active fault detection, artificial seismic exploration, and integrated borehole profile interpretation in Tongling City. It also offers a valuable basis for regional Quaternary stratigraphic correlation, chronostratigraphic division, and reconstruction of sedimentary environmental evolution in the Yangtze River alluvial plain.