Abstract: Sediment is one of the main factors affecting river ecology and environment, playing an important role in maintaining water environment balance and aquatic biodiversity. As the main type of sediment in mountain rivers, wide gradation sediment has unique ecological and environmental effects compared with narrow gradation sediment in plain rivers. With the intensified human activities such as the construction and operation of large cascade reservoirs in mountain rivers, the eco-environmental effects of wide gradation sediment become more complicated. This paper systematically reviews the environmental effects of wide gradation sediment on pollutant adsorption, desorption and transport in mountain rivers, as well as its ecological effects on aquatic microorganisms, animals and plants. And the changes in eco-environmental effects of wide gradation sediment due to cascade reservoirs construction are also analyzed. Then the existing problems in current researches and future research directions are discussed. Therefore, reference for ecological environment protection in mountain rivers can be provided.