There are few reports on the function of transforming growth factor βactivated kinase 1(TAK1) in innate immune response in fish. To explore the role of zebrafish TAK1(Danio rerio TAK1, DrTAK1) in innate immune, a new splicing isoforms of Drtak1 has been cloned and characterized in this study. The open reading frame (ORF) of the Drtak1 has 1 737 nt, which can encode 578 amino acids. DrTAK1 includes a Nterminal serine/threonine protein kinases (S/TKc) and a C-terminal coiledcoil region. The results of immunofluorescence showed that DrTAK1 is a cytoplasmic protein. Overexpression of DrTAK1 in EPC cells downregulates the activity of IFN promoter in luciferase reporter assay in EPC cells. However when cotransferred with zebrafish IRF7, the DrTAK1 can obviously promote the IFNactivation ability of IRF7. The data in this study showed that the DrTAK1 positively regulated IRF7mediated innate immune responses for the first time in zebrafish, and it laid the foundation for subsequent DrTAK1 research.