To study the mechanism underlying the responses of macroinvertebrate functional feeding groups to acid mine drainage and the influence of the Gaolan River pyrite on the ecological environment of the Xiangxi River system, macroinvertebrates were quantitatively investigated at 12 sites along 3 sections (Impacted portion:G1-G3, Recovering portion:G4-G8, Control portion:D1-D4) of the Gaolan River in September and November 2006 and January, March, May, and July 2007; a total of 192 macroinvertebrate samples were collected. Simultaneously, water samples were collected at each site and transported to the laboratory, where their concentrations of 10 metallic elements (Cd, Cr, Cu, Mn, Pb, Zn, Fe, Al, Ca, and Mg) were determined using ICP-AES. Other physical and chemical parameters were measured in the field:pH, conductivity, water temperature, total dissolved solid, salinity, and dissolved oxygen were measured using HORIBA W-23; flow velocity was measured using a hydrometric propeller; water depth and width were measured using a band tape. Comparative analyses were performed to study the macroinvertebrates' functional feeding groups, community structure, and physicochemical parameters among the 3 sections of the Gaolan River. The results showed that metal content, conductance, and total dissolved solids were significantly higher in the impacted section than those in the control and recovering parts, especially at site G1; and there were no significant differences between the control and recovery sections. A total of 213 taxa belonging to 7 classes and 59 families were collected; Baetis sp., Ceratopsyche sp., Serratella sp. and Heptagenia sp. were the dominant taxa, with relative abundances of 18.7%, 11.3%, 9.6%, and 7.2%, respectively. Gather-collector was the main functional feeding group in the Xiangxi River system, followed by scraper, predator, and filter-collector. The shredder feeding group only accounted for a small part, with relative abundances of 48.8%, 20.6%, 17.0%, 9.0%, and 4.7%, respectively. A one-way ANOVA was used to compare densities among the 3 river sections, and the main result showed that the functional feeding group density of impacted sites was significantly lower than those of other river sections. The same analysis was also used to analyze the biodiversity of the functional feeding groups among the 3 river sections. The results showed that the Shannon-Wiener diversity and richness of gathering-collectors, scrapers, and predators were lower in the impacted section than in the other 2 sections, but there were no differences between the control and recovering sections; the two indices of filter-collectors were highest in the control section, followed by the recovering section, and lowest in the impacted section. The diversity indices of Shredders in the control portion were significantly higher than those in the other 2 sections. Non-metric multidimensional scaling and multi-response permutation procedure analysis showed that the community structure of the macroinvertebrate functional feeding group in the impacted river section were significantly different from those of the control and recovering sections. Finally, canonical correspondence analysis was used to study the relationship between functional feeding group communities and physicochemical parameters, the results of which showed that acid mine drainage was the main factor impacting the community structures of macroinvertebrates functional feeding groups in the study area.