Abstract: Objective To study the mutagenic effect of bisphenol A(BPA) on P53 gene in zebrafish.Methods The exposure levels of BPA were determined according to the results of acute toxicity test.Twenty zebrafishes were randomly divided into blank control and exposure group(10 fish in each group).After exposure to BPA for 30 days,the RNA was extracted from liver tissue of the zebrafish and the P53 gene,including a complete coding sequence,was obtained by reverse transcription-PCR(RT-PCR).Results Sequence analyses showed that the length coding sequences(CDS) of the P53 gene is 1 122bp,encoding 373 amino acids and the identical percentage between the published zebrafish sequence and the P53 gene identified is 99.9%,with some differences form P53 of other biotic.After 30 days' exposure,the P53 gene of the exposure group mutated at the concentration of 0.3mg/L.The base substitution of ACA→ACG at codon 86,GAG→GGG at codon 135,AGG→CGG at codon 311 were detected by PCR-directed sequencing.This may result in the Glu→Gly of expressed P53 protein.Conclusion The results show that BPA could induce mutation in P53 gene.Under the experimental conditions,the lowest obsvered effect level(LOFL) of BAA is 0.3mg/L.