This study was carried out to investigate the changes of guilds in benthic macroinvertebrate community in a undisturbed headwater stream. Samples were collected seasonally with a Surber sampler (30×30cm) at three different sampling sites (five replicates in each sampling sites) at Bongsunsa stream in Korean National Arboretum in Gyeonggi-do for 7 years from 2006 to 2012. Physicochemical environmental factors including discharge, water width, substrate composition, dissolved oxygen, pH and conductivity were also measured at each sampling sites. Changes of community indices and functional guilds such as functional feeding groups and trophic groups were evaluated in each sampling sites during study periods. In the samples, 84 species (9 order, 36 family) were identified, and Gammarus sobuegensis, Chironomidae spp, Ephemera strigata and Ecdyonurus kibunensis were dominant taxa. Considering the changes of functional feeding groups, shredder tended to decrease from upstream to downstream, whereas collector-gatherer and collector-filterer became higher. In addition, shredder was higher during autumn seasons. Self-Organizing Map was also applied to find out the temporal changes of benthic macroinvertebrate community composition, displaying the effects of seasonal variations in reference stream ecosystems.