Three stations were determined to study a biodiversity, abundance and distribution of fish in Gave River. For this purpose the slope, height, bottom, water mean rate, … of the river were studied. The Cyprinidae had the most species and 9 genera were identified which 6 of them which contain Alburnus, squalius, Barbus, Capoeta, Garra, Cyprinion were the local genera and 3 of them were nonlocal which came with cultured carps. By the means of 2 genera (Oxynoemacheilus & Turcionemacheilus) were identified. The abundance study showed that in all seasons capoeta damascina in Kolgah station and Capoeta trutta in Agahgoone station and Oxynoemachilus sp in Tapeh Esmaeil were the most species and had the most abundance.