Abstract: Based on ecological characteristics of land types, and by using Zhengning County, Gansu Province locatedon the Loess Plateau as a study area, the coupled relation between ecological suitability and ecological system of land types was studied. The research indicated that there is a satisfactory coupled relation between landtypes and ecological systems, which provides the main basis for land ecological evaluation and construction ofrational ecological system structure. With restructuring rational ecological system and increasing comprehensive ecological functions in Zhengning County as their objectives, the authors proposed ecological construction strategies and measures for the county, which is also helpful to the ecological construction on the Loess Plateau.

Key words: ecological functions, ecological system structure, land type, Zhengning County of Gansu Province