Abstract: Interferon regulatory factor 7 （IRF7） plays important roles in immune regulation, antivirus, and antisepsis, cell proliferation and cell apoptosis, however, the role of IRFs in anti-disease response remains poorly understood. In the report, the recombinant Trachinotus ovatus IRF7（rTroIRF7） protein was prepared in Escherichia coli, purified, and used to produce polyclonal antibodies. The pET32a（+）/Escherichia coli BL21（DE3） expression system was used for the inducible expression of TroIRF7. Under the conditions, 0.1 mmol·L⁻¹ IPTG, 24 h, 20 ℃, the soluble recombinant protein rTroIRF7 was obtained. The molecular mass of the rTroIRF7 protein was 50 kDa. The rTroIRF7 protein was purified by nickel affinity chromatography. The purified fusion protein rTroIRF7 was used as an antigen to immunize mouse for the preparation of polyclonal antibody. ELISA was performed, and the results indicated that the total titer of the polyclonal antibody of rTroIRF7 was 1∶25 600.