Abstract: Manas River basin is one of the most representative mountainoasisdesert ecological systems in arid region of China. There are some differences between the spatial status of regional ecology and economy of the three ecological systems. Through largescale water and soil resources exploitation for several decades, there are different expressive formats of ecoeconomic security problems in different ecoeconomic functional regions during the environmental evolvement and economic development. According to the landuse and water resource data base, referring to natural, economic and social statistical data and aiming at ecoeconomic security problems of different subdivided regions, this paper selected corresponding indexes of ecorisk assessment based on subdivided ecoeconomic functional region. And combining field investigation and expert evaluation, the weight of different indexes were confirmed and the ecosecurity assessment indexes were calculated. Analyzing the assessment results, it could be drawn as follows: (1) Manas river basin can be divided into three regions and 9 subdivided regions. According to ecological security problems of different ecoeconomic functional regions, 13 ecologicalenvironmental and 4 socioeconomic indexes were selected. (2) the ecoinsecurity indexes of subdivided region Ⅱ4, Ⅲ1 and Ⅲ2 increased and Ⅲ3 decreased gradually, and that of Ⅰ1,Ⅰ2,Ⅱ1,Ⅱ2 and Ⅱ3 fluctuated. Due to the four subdivided regions of oasis, the ecoinsecurity indexes of Ⅱ2 was the maximum and there were many ecosecurity problems. While, the subdivided region Ⅱ3, which was in the edge of desert, had the minimum ecoinsecurity index. So, not only the region with a high ecoinsecurity index needed recognition, but also the region with many disadvantage effects because of ecological problems needed recognition.

Key words: Manas River basin, oasis, subdivided ecoeconomic functional region, ecosecurity assessment