Abstract: 【Objective】Nonylphenol (NP) is an environmental estrogen pollutant. The study was to explore the toxic effect of NP on the embryonic development of Carassius auratus cuvieri, and to investigate the improvement of the NPinduced toxicity by tea polyhenols.【Method】The tail bud embryos were exposed to different concentrations of NP, and the toxic effects of NP on the embryonic development of C. auratus cuvieri were analyzed by comparing the changes of hatching rate of embryos and the abnormal rate of larval under toxic treatment, with the clear water as control group. Subsequently, the embryos were soaked in NP liquid added with tea polyphenols, and the changes of the hatching rate and the abnormal rate were compared between NP control group and tea polyphenols experimental group in order to judge the improvement effect of tea polyphenols.【Result】Compared with the ethanol control group, the low and the medium concentration of NP (0.04-0.40 mg/L) not only reduced the hatching rate of embryos significantly but also increased the abnormal rate of larvae significantly, and the abnormal rate increased with the increasing of NP concentration. The high concentration of NP (4.00 mg/L) had strong toxicity to embryonic development, and the embryos with this concentration stopped to develop within 24h of exposure to NP. After adding the tea polyphenols (0.35-35.00 μg/L) into NP, the tea polyphenols (3.50 μg/L) could significantly improve the hatching rate of embryos. There was no significant difference in hatching rate between other experimental group and NP control group. In addition, 0.35-35.00 μg/L tea polyphenols could significantly reduce the abnormal rate of larval induced by NP.【Conclusion】NP has certain toxicity to the embryos of C. auratus cuvieri, and adding appropriate amount of tea polyphenols can improvement the embryonic toxicity induced by NP.