Wujiang River is the longest river in Guizhou province and one important tributary of Yangtze River. To explore the original data about species composition and diversity of fishes in Wujiang river, we conducted 12 field surveys at 135 sites in Guizhou province from 2017 to 2021. A total of 5 065 fish specimens (weight about 204 kg) were collected, and 107 species belonging to 6 orders, 22 families, 73 genera were identified. Cyprinidae had the largest number with 53 species, accounting for 49.53%. Species diversity G-F index of different areas of Wujiang River were 0.40, 0.47 and 0.45 from upper to lower reaches, showing that upper stream has lower species diversity within family and genus than middle or lower streams. In middle Wujiang River, the Shannon-Wiener diversity index (H') was 3.54, Margalef richness index (D) was 9.63, Pielou evenness index (J') was 0.81. Results showed that the first ten species with weight and number included：Spinibarbus sinensis, Oreochromis niloticus, Saurogobio dabry, Carassius auratus and Hemiculter leucisculus. According to Index of Relative Importance, the dominant species (IRI>500) in middle reaches of Wujiang river were C. auratus, H. leucisculus, S. sinensis and Opsariichthys bidens. This study showed that construction of dams would be the main factor to impact species composition of Wujiang River. This study could provide important data for species composition and diversities of Wujiang River, and it would be valuable to evaluate the effect of ten-year fishing ban policy of Yangtze River.