Abstract: This paper systematically invested the fish resources included 3095 individuals of the Xiquanyan Reservoir and identified 30 fish species,which belonging to 6 orders,11 families and 30 genera.And the carp families had 21 species and occupied 70% of the total number.And also analysis the fish diversity of the reservoir by three methods such as Pinkas relative importance index,Shannon-Weaver diversity index and Pielou evenness index.The Pinkas relative importance index about Xiquanyan Reservoir（IRI）draw a conclusion that the middle and small fish had three dominant species,which including Hypomesus olidus、Hemiculter leucisculus and Saurogobio dabryi;the dominant species of the stocked carps were Hypophthalmichthys molitrix and Aristichthys nobilis.The Shannon-Weaver index value（H′）varied from 0.1373 to 0.2129 and the Pielou index value varied from 0.0404 to 0.0626.General,the fish diversity in Xiquanyan Reservoir were in low level and the stability was bad.Finally,the paper proposed the protective suggestions of fish species diversity in Xiquanyan Reservoir.

Key words: Xiquanyan Reservoir, Fish community structure, Biodiversity