This paper compares and studies the strahler integral value S, theinformation entropy valuq H and the shape index N of river gully longi-tudinal section in rectangle basin,considers N as the index of therectanglebasin geomorphy developing stage. At the same time, this paper utilizesthe information of the three rivers (Jinsha River, Lancangjiang Riverand Lujiang River) basin in the northwest of Yunnan, demonstrates theindexes above all,at last draws the information of the developing stagein the cause of eroding circle and the information of the stability inerosional basin.