Abstract: Scientific evaluation of ecological carrying capacity of a region is an important link to development and management of ecotourism therein. Analysis and evaluation was performed of the supply and demand of ecological carrying capacity in the middle and upper reaches of the Nanxi River Basin in 2010. Results show that the supply was higher than the demand, being at a ratio of 1.3:1; however, deficits still appearared in the carrying capacity of the fractions of grasslands and waters; the ecological footprint per traveler was 1.22 times as higher than as the local per capita ecological footprint. On the whole, the ecological carrying capacity of this basin is enough to support benign development of ecotourism. Nevertheless, it is essential not only to strengthen continuous conservation and input of its ecotourislogicalt resources, but also to pay high attention to supervision and restriction of flow-based tourism.