Aim To explore the effect of heat shock protein 70(HSP70) on Bcl-2 expression and investigate the role of Bcl-2 in HSP70's anti-apoptosis in C2C12 cells. Methods Westen Blotting were used to identify the expression of Bcl-2 in the C2C12 cells transfected with pcDNA3.1-HSP70 or HSP70's antisense oligonucleotide.The apoptosis were analysed by flow cytometry in the HSP70-overexpressed C2C12 cells which were transfected with Bcl-2's antisense oligonucleotide and then treated with H2O2(0.5 mmol/L). Results The expression of HSP70 and Bcl-2 was increased in the C2C12 cells transfected with pcDNA3.1-HSP70,but the expression of HSP70 and Bcl-2 was decreased in the C2C12 cells transfected with HSP70's antisense oligonucleotide.In the HSP70-overexpressed C2C12 cells transfected with Bcl-2's antisense oligonucleotide,H2O2-induced apoptosis rate was higher than that in the cells transfected with Bcl-2's scramble oligonucleotide. Conclusion HSP70 contributed to the upregulation of Bcl-2 expression;Bcl-2 played an important role in HSP70-mediated protection against H2O2-induced apoptosis.