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.