Abstract: To study the effects of different riparian vegetation densities on river evolution is practically significant for predicting the river evolution process in flood period and the ecological river engineering of artificial planting vegetation. In this work, a natural model experiment method is used to study the influence of different riparian boundary conditions of a river channel on its stability characteristics, bank erosion, and sediment transport intensity, by varying planting density and comparing single-bank planting and double-bank planting. The results show that (1) The riverbank is eroded differently with or without vegetation coverage. (2) With single-bank planting, the river bend has a poor stability, while with double-bank planting of larger coverage rate, it is easier for a river to form composite cross sections with a stable narrow, deep channel. (3) The variation in near-bank bed elevation is increased with an increasing coverage rate. Riparian vegetation plays a positive role in river bend stability and bank erosion resistibility, but it intensifies near-bank bed cutting.