Grain-size can be applied to identify types of deposition environment and to determine ways of material movement.Based on the investigation on the beach of Weihe River in Xianyang section,and the analysis of grain-size for 53 collected samples,the characteristics of flood sediment were analyzed,including grainsize distribution,grain-size parameter,and grain-size frequency curve.Results showed that the thickness of modern time flood sediment in the Beibuzi section of Weihe River was about 2.16 m.For the grain-size composition,the content of medium size sand was the highest,its grain-size was in the thick range,and its size sorting was worse.Based on the analyzed material,the development of flood sediment was better over the past 30 years.