Based on the research of Qingyi River terraces， locating in the southern range of the Longmen Shan， weathering characteristics calculated with major elements are discussed to solve the problem of terraces contrast， and some progress has been made. By analyzing the major elements， CIA index， A—CN—K triangular model are texted in order to distinguish terraces with different ages， which is proved to make sense. And the color of matrix in fluvial deposition is able to tell the difference of terraces to a certain extent. With the help of research about the alluvial fan formed by ancient Qingyi River， it is found that the rate of chemical weathering is smooth， but the older geomorphic surface weathering is nonlinear. Additionally， within 600ka time scale of this study， terraces weathering rate is influenced by global climate change， the main performance is a low weathering rate in during an glacial epoch and， on the contrary， a fast weathering rate during an inter—glacial epoch. As an addition， the effect lags behind the change of climate.