Abstract: An investigation of fish composition and biodiversity in Pingchuan section of the upper reaches of Hanjiang River was made in May-June, 2016. A total of 29 species were collected, belonging to 25 genera, 5 families, and 3 orders. Cyprinidae was most abundant (21 species, 74.41% of the total species), followed by Loach (5 species, 17.24% of the total species). The horizontal distribution of fish species diversity appears rare in the middle section and abundant in the upper and lower sections. The vertical distribution of fish diversity according to the regular pattern that species diversity decreases when altitude increases. The method of non-metric multidimensional scale sorting (NMDS) was used to analyze the distribution characteristic of fish communities. Canonical correspondence analysis (CCA) was used to analyze the relationship between fish spatial distribution pattern and water environmental factors. NMDS showed that there were no obvious clustering characteristics in the fish population distribution at each station. CCA analysis showed that the community structure of fish was effected by the conductivity of water biochemical oxygen demand in five days, pH and sulfate concentration remarkable (all P<0.01) in Pingchuan section of Hanjiang River.