Abstract: We studied the influence of triazophos on sex hormone levels, apoptosis, activity of related protease caspase and microstructure of Perna viridis gonad, so as to discuss the endocrine disrupting mechanism and reproductive toxicity of triazophos on P.viridis. The results show that triazophos reduced the contents of β-estradiol and testosterone in gonads of P.viridis (P>0.05), suggesting that triazophos can exert its endocrine-disrupting effects by reducing sex hormones levels. In addition, the response of caspase-3 and caspase-9 activities in the gonads of P.viridis to triazophos exposures were gender-specific. The activities of caspase-3 and caspase-9 in female and male mussels were depressed and induced significantly at different time intervals, respectively, which indicates that triazophos influences the enzyme activity of apoptosis in mussel gonads to affect the apoptosis process. Moreover, the number of reproductive cells decreased and the reproductive cells were more loosely arranged and deformed in P.virudis gonads after triazophos exposure. The results reveal that triazophos shows endocrine disrupting effects and has reproductive toxicity on P.viridis.