As a kind of flame retardants, polybrominated diphenyl ethers (PBDEs) have been widely applied in industrial products and house wears, and detected in soil, sediments, air, and living organisms. PBDEs are proved to be harmful to mammals, birds, and fish. Great concern has been aroused because of their wide spreading, stable structure, and uncertain risk to human health. Based on the foreign toxicological researches and findings, this paper summarized the accumulation and elimination of PBDEs in organisms, their effects on the hepatic enzyme activities, thyroid gland, nerve and immune system, and reproduction and development of animals, and potential risk to human health. The problems in PBDEs toxicological research were analyzed, and future directions in this field were discussed.