Abstract: During the past decades,the ecological impact of hydropower development has been drawing an increasing attention worldwide. In the mountainous area of southwest China,numerous studies have reported that the increasing dams are threatening the local biodiversity. In order to understand the effect of dams on native small vertebrate community,pitfall trips were used to survey the community composition, abundance,and distribution pattern of small vertebrates crossing three sampling habitats:the dam construction area,upstream and downstream areas of the dam. The study was conducted from April to June, 2010 in the Sier River basin within the Xuebaoding National Nature Reserve,Sichuan Province. 19 pitfall traps were set up and 117 animals of 18 species were captured with a survey effort of 1 140 trap-nights. They belongled to 9 families,5 orders,3 classes. The small vertebrates captured during the survey included 8 amphibian species (29 individuals,24.8%),8 mammal species (63 individuals,53.8%) and 2 reptile species (25 individuals,21.4%). Five dominant species (85 individuals) accounted for the majority (72.6%) of captured animals:Sorex minutus,Sphenomorphus indicus,Rattus norvegicus,Bufo andrewsi and Bufo gargarizans. The structure pattern of the community fitted the negative distribution. The animal abundance of the construction area was significantly lower than that of the downstream area,and the species richness of the construction area was significantly lower than that of the upstream area. The results indicated that the construction of minor-dam had a negative impact on the local community of small vertebrates. This study provided the baseline for evaluating the ecological impact of minor-dam construction and developing future conservation strategies accordingly.