Abstract: The Huaihe River Basin lies in the climate-sensitive transition between northern and southern China, where monsoon influences contribute to frequent flooding. Based on field investigations of the Huaihe River Basin, a sedimentary profile containing five overbank flood deposits (OFD1–OFD5) was identified on the steep cliff of the front slope of the first terrace along the northern bank in Zhengyang reaches of the upper Huaihe River Basin. Particle size, magnetic susceptibility, and optically stimulated luminescence (OSL) dating analyses were performed on collected samples. The results indicated that 1) the particle size composition of OFDs was dominated by coarse silt (> 48%), whereas that of the palaeo-floodplain and palaeo-riverbed sand layers was mainly sand (> 88%). The particle size distribution frequency curves and end-member analysis demonstrated that the frequency peaks of OFD1–OFD5 consistently fell within the coarse silt range, demonstrating that OFDs were derived from sediments eroded by hydrodynamic processes on both sides of the valley and subsequently transported and deposited in an overbank environment. 2) The low-frequency magnetic susceptibility values of OFDs were intermediate between those of the modern topsoil and palaeo-floodplain sand layers. Among them, OFD5, OFD4, and OFD3 (41.13 × 10⁻⁸, 44.5 × 10⁻⁸, and 37.9 × 10⁻⁸ m³/kg) exhibited notably higher values than OFD2 and OFD1 (7.17 × 10⁻⁸ and 6.53 × 10⁻⁸ m³/kg), which could be due to variations in weathering and pedogenesis following deposition. 3) OSL dating and stratigraphic analysis revealed five major palaeoflood events between 1800 and 1400 yr during the late Holocene in the upper Huaihe River. These events coincided with pronounced climatic fluctuations and El Niño–Southern Oscillation activity. This interval also corresponded to severe climatic deterioration during the Wei, Jin, and Northern and Southern Dynasties (220–589 AD) in China. The flood record provides geological evidence of the regional hydrological response to global climate change during this interval. By integrating these flood records with abrupt climate variability and monsoon dynamics, this study offers essential insights for advancing flood control and disaster mitigation strategies in the basin.