Using detailed description of deposits in six boreholes，grain size analysis data of sediment samples，results of previous studies on historical changes of the lower reaches of the Yellow River and dating results in the study area，we investigated the sedimentation characteristics and environmental changes in the floodplain of the lower reaches of the Yellow River from 602 BC to 11 AD. It is found that the ancient ground surface around 602 BC can be determined exactly by integrating the evidence such as changes in color，composition，texture，and grain size of the sediment samples from the boreholes in the study area，and the parameter Kd can also be used as a good indicator of the boundary. The sediments accumulated on the floodplain of the lower reaches of the Yellow River after 602 BC are mainly composed of light yellow，yellow，brown silt，sandy silt，and silty clay. They are characterized by poor sorting，with an average grain size of 331 to 612Φ，a positive or very positive skewness，and a medium，narrow，and very narrow kurtosis. From the upper reaches to the lower reaches of the Yellow River,the average grain sizes become finer，and standard deviation increases and kurtosis decreases，indicating a decrease of both hydrodynamic forces and sorting. The results of nonparameter analyses show that the deposits accumulated from 602 BC to 11 AD are markedly finer than those in the modern floodplain of the lower reaches of the Yellow River. The variations in the Kd value of deposit samples indicate that the hydrodynamic forces changed at least twice during the period from 602 BC to 11 AD.