关键词: 侵蚀积分值, 侵蚀模数, 动力学机制

Abstract: In this paper .the concepts of entropy ,flux and force in the drainage-geomorphic system have been introduced ,and an equation for the entropy production and super-entropy production has al-so been conducted，According to this concept,dynamic mechanism in the drainge-geomorphic sys-tem is analysed ,and an evolutional model for the development the drainage-geomorphic system in a hill-gully area on the loess plateau is developed. The model is suitable for the entire process of drainage-geomorphic system. By using this model the erosional cycle in the hill-gully area can be divided into three stages. By quantitatively analysing the Erosional Cycle Theory of Davis and dif-ferent soil erosions at the different stages，non一uniform erosional properties of a drainage-geo-morphic system in space is also founded.

Key words: Erosional intergral value, Erosional modals, Dynamic mechanism