Abstract: Polybrominated diphenyl ethers (PBDEs) and their metabolites (hydroxylated PBDEs) are excellent flame retardants and have wide applications in daily life, but it has been concerned that most of these chemicals are endocrine disruptor damaging the function of thyroid hormone. The toxicity of PBDEs and OH-PBDEs on embryos at early development and the effects on deiodinase were summarized in this review.