To obtain soluble recombinant Cyprinus carpio IL-17N protein, recombinant prokaryotic expression plasmids (GST-17N, SUMO-GST-17N, MBP-17N) were constructed, the optimal fusion tag(GST, GST-SUMO and MBP) was determined, and the expression conditions of recombinant Cyprinus carpio IL-17N protein (the content of IPTG, time and temperature) were optimized. Results: the recombinant Cyprinus carpio IL-17N prokaryotic expression plasmids (GST-17N, SUMO-GST-17N, MBP-17N) were successfully constructed. The soluble expression of rccIL-17N protein from high to low were MBP-17N, SUMO-GST-17N and GST-17N. The soluble protein of SUMO-GST-17N and MBP-17N accounted for 47.4% and 87.0% of the total protein, respectively. The optimal induction condition for MBP-17N was incubate the transformed Escherichia coil for 8-12 h under 25 ℃ with 0.5 mmol/L IPTG induction. The prokaryotic recombinant protein was purified by Ni-NTA and 0.09 mg protein could be obtained by 1 g total bacterial.