Pancreatic ribonuclease (RNase 1) is an important digestive enzyme that has been used to study the adaptative evolution of some herbivores to herbivorous diet. Although there have been many functional studies of RNase 1 in mammals,there is little research in fish. In this study,we identified and analyzed the RNase 1 genes from 9 cyprinid fish including herbivorous Ctenopharyngodon idella and Megalobrama amblycephala,omnivorous Hypophthalmichthys molitrix,Hypophthalmichthys nobilis,Cyprinus carpio,Xenocypris davidi and Danio rerio,carnivorous Culter alburnus and Elopichthys bambusa. We also detected the relative expression of the RNase 1 gene in different tissues in 4 fish species with different feeding habits (M. amblycephala,A. nobilis,C. alburnus and C. idella). The results showed that there was only one RNase 1 gene in the genomes of the 9 cyprinid fishes,and all the 9 identified fish RNase 1s have the signature motifs of the RNase A superfamily:N-terminal signal peptide,six conserved cysteine residues,the catalytic histidine-lysine-histidine triad and CKXXNTF motif. Phylogenetic analysis indicated that all the fish RNase 1s were clustered together. The RNase 1 genes expressed differently in different tissues of the 4 fish with different feeding habits,mainly expressed in the livers but not in the intestines.These results suggest that the evolution of RNase 1 in Cyprinidae is not related to the food habit of the species, but conforms to the evolutionary law of the species.