Interleukin-17 (IL-17) plays an important role in inflammation and host defense in mammals. To investigate the biological function of CcIL-17N, two CcIL-17N genes were identified from the common carp (Cyprinus carpio) whole-genome using BLAST and gene cloning performed by genomics, named as CcIL-17Na and CcIL-17Nb, respectively. They were encoded by the complementary sequence of intron 2 of the TOP3B gene. Synteny analysis indicated that SDF2L and PPM1F were present on both sides of IL-17N, except for Takifugu rubripes. These two IL-17N isoforms encoded 136 amino acids, including 3 exons, and exhibited 97.1% similarity in sequence. The similarity between CcIL-17Na and CcIL-17Nb of common carp with other teleosts were estimated to be 65.3%-97.1%, 64.7%-96.3%, and of 32.9%-51.4%, 31.4%-50.7% in comparison with other IL-17 family members in common carp. The phylogenetic tree of teleost IL-17 family members showed that 7 members constitute 6 credible branches, of which IL-17A/F1 and IL-17A/F3 constitute a branch, and the remaining six members form a branch separately. IL-17N of common carp was clustered with zebrafish and grass carp with a bootstrap of 95%, with medaka, T. rubripes, tilapia, etc. clustered with a bootstrap of 84%, with Lepisosteus osseus IL-17N with a bootstrap of 70%, and finally coelacanth IL-17N with a bootstrap of 97%. CcIL-17Ns expression level at 0.5 and 12 h after fertilization was significantly higher than that at 25, 35, 60, 120 h, and larval fish stage (P<0.01). CcIL-17Ns expression in the brain of summerlings and adult fish was the highest, which was significantly higher than other tissues (P<0.05 or P<0.01). CcIL-17Ns expression in all tissues was up-regulated under Aeromonas hydrophilis infection. CcIL-17Ns expression in the brain was significantly up-regulated for 6 h after infection (P<0.05). At 1 d, CcIL-17Ns expression in other tissues was significantly up-regulated, and the expression was decreased for 3 d and 7 d after infection, with no significant difference from the control group (P>0.05). Recombinant prokaryotic expression plasmid pMAL-c2X-17N was constructed and transformed into Escherichia coli Transetta (DE3) for prokaryotic expression. Soluble recombinant common carp IL-17N protein (rccIL-17N, MBP-17N) was obtained by Ni-NTA. Under the induction of different concentrations of MBP-17N protein (0.1, 1, 10, and 100 ng/mL), kidney tissue was incubated for 8 h. qPCR indicated that IL-1β and NF-κB was significantly up-regulated at 0.1, 1, 10, and 100 ng/mL of MBP-17N. IFN-γ was significantly up-regulated under 1 and 10 ng/mL MBP-17N, whereas IL-6 was significantly up-regulated at 0.1 and 1 ng/mL. CCL20 was significantly up-regulated at 1, 10, and 100 ng/mL. Furthermore, TRAF6 gene significantly upregulated at 1 ng/ml than that of the control group. In conclusion, this study revealed that ccIL-17N was highly conserved in evolution. Meanwhile, ccIL-17N is involved in inflammatory response based on its role in A. hydrophila infection and rccIL-17N function.