Abstract: Effect of tributyltin chloride(TBTCl) on apoptosis of spermary cells of male Oreochromis aureus was studied through an experiment,where TBTCl was dissolved in the water the fish were kept in at a dosage of 0,1,3,5 and 10 μg·L^-1,respectively.Spermaries of the fish were taken after exposure for 24 or 48 hours.Part of the organ was prepared into paraffin section for analysis of apoptosis by terminal deoxynucleotidy transferase mediated dUTP-Biotin nick-end labeling(TUNTEL),while the other part was used for study of effect of TBTCl on activity of Ca²⁺-ATP enzyme in the spermary cell.Results show that apoptosis of spermary cells was induced by TBTCl,and activity of the Ca²⁺-ATP enzyme of spermary cell varied between treatments of dosage of TBTCl after exposure for a set period of time.Regardless of exposure time,whether 24 or 48 hours and 24 or 96 hours,no significant difference(P>0.05) was observed between the 1 μg·L^-1 group and the control group in apoptosis and in variation of Ca²⁺-ATP enzyme activity,respectively.Under the condition of effective dosages,spermary cell apoptosis rate increased with the dosage,showing a close relationship(P<0.05) between dosage and apoptosis rate.Similarly,the activity of Ca²⁺-ATP enzyme also increased along with the dosage of TBTCl(P<0.05).When the dosage of the TBTCl increased,the apoptosis rate and the activity of Ca²⁺-ATP enzyme of spermary cells increased synergetically.