Objective:To investigate the molecular mechanisms by which SARS-CoV-2 accessory protein ORF7a mediating NF-κB activation and thus inducing inflammatory cytokines production.Methods:Effects of ORF7a on NF-κB promoter activity was analyzed by luciferase reporter assay.qRT-PCR was used to analyze expressions of inflammatory cytokines.Effects of ORF7a on phos-phorylation and nuclear-translocation of p65 were determined by Western blot and immunofluorescence.Co-immunoprecipitation and immunofluorescence assay were performed to investigate potential target s of ORF7a.Results:Luciferase reporter assay showed that ORF7a activated NF-κB promoter activity in a dose-dependent manner(P<0.001),while has no effect on activation of AP-1 reporter gene.ORF7a significantly upregulates expressions of TNF-α,IL-1β and IL-8 mRNA levels(P<0.05).Western blot showed that ORF7a markedly increased phosphorylation of p65 protein(P<0.05)and p65 nuclear localization(P<0.01).The interaction between ORF7a and IKKβ protein of NF-κB signaling pathway was found by immunoprecipitation assay,and the co-localization of ORF7a and IKKβ was also confirmed by immunofluorescence assay.Conclusion:SARS-CoV-2 ORF7a targets IKKβ to promote active NF-κB pathway to the release of inflammatory cytokines.