Based on quantitative investigation from July 2004 to June 2007 in Xiangxi River, the largest tributary in Hubei portion of Three-Gorge Reservoir, macroinvertebrate functional feeding groups were studied; some indices based on FFGs were used to evaluate river ecosystem. The results showed that gather-collectors were the main component in Xiangxi River system, followed by scrapers, and predators, filter-collectors, shredders only accounted for a small part. Every FFGs distribution was significantly different among seasons and tributaries in Xiangxi River. By analyzing the spatio-temporal distribution of some indices based on FFGs, the results showed that material cycling capability, lateral input capability, CPOM input/ FPOM input in Jiuchong River were much better than the other rivers, and they were much better in winter than in other seasons. Longitudinal transport capability was best in Gaolan River; and it was also better in winter. Stepwise regression analysis showed that material cycling could be mirrored by water velocity, conductivity, turbidity, total nitrogen, SiO2; Longitudinal transport could be mirrored by SiO2 and chemical oxygen demand (COD); Lateral input capability could be mirrored by water temperature, water depth, SiO2, total phosphorus; and CPOM input/FPOM input was maily mirrored by water temperature and SiO2.