Objective: To explore whether IRE1α can mediate unfolded protein response (UPR) during embryo development of xenopus laevis and rescue the developmental defects induced with tunicamycin. Methods: IRE1α mRNA or specific antisense oligonucleotids morpholino were microinjected to the 4 blastomeres of 4-cell stage embyos to overexpress or knockdown gene expression;the splicing of XBP1 was tested with RT-PCR to reflect the UPR;Tunicamycin was used to treat the embryos to induce the endoplasmic reticulum stress (ERS). Results: The splicing of XBP1 was increased when IRE1α was overexpressed while the splicing was decreased when IRE1α was knockdwon. Embryos developmental defects and the increase of XBP1 splicing were induced with tunicamycin while knockdown of XBP-1 partially rescued the defects and knockdown of IRE1α rescued the defects significantly and the increased XBP1 splicing. Conclusion: IRE1α can mediate UPR during xenopus development. Knockdown of IRE1α rescued the developmental defects induced with TM and partially by the IRE1α/XBP1 pathway.