Abstract: Sediment grain analysis (SGA), as the fundamental work of sediment research, could provide information for river evolution, aquatic ecological environment and geological landforms. In this research, current SGA methods are categorized, the advantages and disadvantages as well as the application scope of each method are assessed, and the calculation principle of each method are summarized. An analysis tool called GRADSTAT is applied to the analysis of bed material sediment samples collected from Minjiang River, and the results show that the sorting of bed material in Minjiang River is inferior, the grain size of sediment decreases along the river, and there are many fine-grained sediments in the downstream bed material because of the interception by upstream reservoirs.

Key words: sediment grain size analysis, GRADSTAT, bed material, Minjiang river