Abstract: On the basis of the erosion characteristic, the erosion adjustment law of braided reach in the downstream reservoir under strong and week constraint conditions is analyzed. The study results indicate as follows: ①The feature of channel scouring course is to degrade first and then widen, the influence of river-bed composition on the magnitude of erosion in longitudinal and transverse directions is very distinct. ②The erosion adjustment process of the strong constraint braided channel shows the river-bed morphology variation, the cut-down of sand channel and gravel channel and change of division ratio. ③The erosion adjustment process of weak constraint braided channel presents as the collapse of shoreline, erosion and cutting of beach, alternating of the main and secondary branches and largely horizontal oscillation of the main channel. And the key factors ?which influence the erosion adjustment of braided reach are also concluded.