中文摘要：

明渠非恒定流流速分布及非恒定流作用下推移质运动分别是水力学和泥沙运动力学研究中的重要问题之一。近几十年来，国内外许多学者在这些领域做过很多探索，取得了一定进展，也存在较多问题。在总结相关研究成果的基础上，简述了明渠非恒定流试验方法、流速分布、床面切应力、非恒定流输沙与水流运动不同步现象、产生原因、以及非恒定流推移质输沙公式等方面的成果，指出了现有研究中存在的不足，提出了需要进一步研究的关键问题：应用先进的量测仪器，研究非恒定流作用下非均匀沙运动输移规律。

英文摘要：

The vertical velocity profile and bed-load transport in unsteady open-channel flow are major concerns of hydraulics and mechanics of sediment transport.In recent years,many researchers have come to do some serious explorations into the nature of the problems.Progresses on the subject are achieved and challenges for future research are pointed out.In this article we provide an overview of related research achievements including the experimental methodology,the vertical velocity profile and the bed shear stress in unsteady open-channel flow,the flow-sediment hysteresis effect and its reasoning,and the bed-load transport formula.Major deficiencies in current work are pointed out and future research suggestions of topics for focus issues are provided,which includes the study of the law of non-uniform sediment transport in unsteady flow with the advanced instruments.