Arsenic is a grade l human carcinogen that can cause kinds of damage to the body.The heart is one of the main target organs of arsenic damage,but the preventive and curative measures underlying arsenic poisoning are not clear.To investigate the effect of tanshinone llA sulfonate on the injury of H9C2 cardiomyocytes induced by NaAsO2,H9C2 cardiomyocyteswere divided into four groups where control group with general medium,arsenic group received sodium arsenite which containing general medium,STS pretreatment and As group and finally the STS alone group.Compared with the control group,different concentrations of STS had no significant effect on the cell viability; Compared with the control group,there was no significant change in the viability of cells treated with arsenic for 12 h after STS pretreatment for 6h,the viability of cells treated with NaAsO2 alone was decreased;Compared with the control group,the cell viability was decreased after STS pretreatment for 12h and arsenic for 24h,the cell viability of NaAsO2 group was also decreased,the viability of NaAsO2 cells was lower than that of STS pretreated for 12h with NaAsO2 for 24h.The content of Caspase 3 and 7 in the NaAsO2 group was higher than that in the STS and NaAsO2 group and the Control group and STS group after 12h,the differences were statistically significan.After STS pretreatment for 12h and NaAsO2 for 24h,there was no significant difference in Caspase 8 content between NaAsO2 group and other groups;As a result,Sodium tanshinone llA sulfonate can attenuate the injury of H9C2 cardiomyocytes induced by sodium arsenite.