Shrimp aquaculture has been seriously affected by acute hepatopancreatic necrosis disease (AHPND), caused by a strain of that carries the Pir toxin plasmids ( ). In this study, the transcription factor, Kruppel homolog 1-like of (Kr-h1), was significantly induced in shrimp hemocytes after challenge, suggesting that Kr-h1 is involved in shrimp immune response. Knockdown of Kr-h1 followed by challenge increased bacterial abundance in shrimp hemolymph coupled with high shrimp mortality. Moreover, transcriptome and immunofluorescence analyses revealed that Kr-h1 silencing followed by challenge dysregulated the expression of several antioxidant-related enzyme genes, such as Cu-Zu SOD, GPX, and GST, and antimicrobial peptide genes, i.e., CRUs and PENs, and reduced ROS activity and nuclear translocation of Relish. These data reveal that Kr-h1 regulates shrimps' immune response to infection by suppressing antioxidant-related enzymes, enhancing ROS production and promoting nuclei import of Relish to stimulate antimicrobial peptide genes expression.