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This paper describes valley bottom troughs of the Changjiang River and infers thegeomorphologic development of troughs. Based on the morphology of the troughs, the followingconclusions are drawn. (1) The deep troughs on the Three Gorges valley bottom are formed by riverdowncutting along the structural zones on the background of regional tectonic uplift at about 40-30ka BP. (2) When river downcutting occurred in the river bed of Changjiang, the jets current(particularly eddy current) with a large number of pebbles ground and eroded the valley bottom,
Based on the morphology of the troughs, the followingconclusions are drawn. (1) The deeproughs on the Three Gorges valley bottom are formed by riverdowncutting along the structural zones on the background of regional tectonic uplift at about 40-30ka BP. (2) When river downcutting occurred in the river bed of Changjiang, the jets current (particularly eddy current) with a large number of pebbles ground and eroded the valley bottom,