The objectives of the study were to determine fish fauna and compositions during 2010~2011 in Walpyung Conservation Park along with analysis of fish community structures and trophic and tolerance guilds. Total number of species and individuals sampled were 31 and 2667, respectively and dominant species was Zacco platypus (46.6%) and subdominant species was Acheilognathus lanceolatus (8.7%),which were composed of >50% of the total, Total number of Korean endemic species including Microphyogobio yaluensis was 10 and the proportion of the individuals was 8.7%.Also,natural monument No.454 of Iksookimia choii, which is endangered species and legal protected species, was sampled and the total number of individuals was only three. According to the analysis of fish community structures, species richness index in the mid-stream reach(M(r)) was 3.145,which is higher than any other stream reaches(U(r) and D(r)).In contrast, the richness index was 2.180 in the up-stream reach (U(r)),which is minimum among the sampling sites. Species, Species diversity index was 1.785 and 1.975,respectively in the headwater (U(r)) and mid-stream reach (M(r)) and the low values in the doun-stream reach (D(r),1.660) were due to the influences of point-source(i.e., road construction) and non-point sources (sporadic agricultural spots).According to analysis of tolerance guilds, the proportion of tolerant species (TS),based on the number of individuals, was composed of 64.2% and sensitive species (SS) was only 3.3%,indicating a predominance of tolerant fishes in the compositions. The proportion of omnivore species (OS),however, was composed of 64.0% and insectivore species (IS) was 29.3%,indicating a predominance of omnivore fishes in the stream. The high proportions of tolerant and omnivore species in this stream indicates that the water quality and physical habitat environments were degradated in this system. For these reasons, especially natural monument and endemic fish species in this region should be protected from the massive constructions and required to provide efficient stream management strategies.