///Based on the study of the fluvial geomorphology along the Jinsha River from the estuary of Yalongjiang to Jinpingzi by using the methods of sedimentology, geomorphology and chronology, combining with the character of geomorphology and the Cenozoic sediment in this region, the authors suggest that the development of reach can be divided into four stages, i.e, 1) the river developing on the plateau (7~4.2 Ma), 2) the lake and basin developing on plateau (4.2~1.1 Ma), 3) the ancient water system developing (1.1~0.73 Ma), and 4) the eastward flowing of Jinsha Rriver (0.73 Ma). 7~4.2 Ma, the river developed after planation surface discomposed. These ancient lakes in Panzhihua area and Yuanmou did not link. The ancient Shenyu River divagated and flawed eastward, but not run through. 1.1~0.73 Ma, the ancient Shenyu river run through and formed the Jinsha River. The developed of Yuanmou Formation finished. 0.73 Ma to now, the bank of 1 200~1 400 m along Jinsha River had formed steep slop under speedy incising of the river. Terraces have begun to form since the late middle Pleistocene.