〔Abstract〕 Objective To explore the effects of microRNA-155(miR-155) on apoptosis of chronic myeloid leukemia( CML) cells,and the influence of miRNA-155 regulating the expression of heat shock proteins( HSP) 27,HSP60,HSP70. Methods Reverse transcription-quantitative real-time PCR( RT-q PCR) was used to detect the expression levels of miR-155 in CML-resistant imatinib( IM) cell line K562-G and CML cell line K562. K562-G cells were infected with the lentivirus carrying miR-155 or the negative control lentivirus,and they were named miR-155 group and control group. The effect of miR-155 on the proliferation of drug-resistant cells was detected by cell counting kit-8( CCK-8) method. RT-q PCR and Western blot were used to detect the effect of miR-155 on the expression of heat shock proteins HSP27,HSP60,HSP70. Flow cytometry was used to detect the percentage of cell apoptosis in miR-155 group and control group. Results Compared with K562 cells,miR-155 showed low expression in K562-G cells( P<0. 05). The proliferation of miR-155 group cells decreased significantly from the 36th hour( P<0. 05). Compared with the control group,in the miR-155 group,HSP60 and HSP70 increased( P<0. 05),while HSP27 decreased( P<0. 01). The apoptosis rate of miR-155 group was higher than that of control group( P<0. 05). Conclusion miR-155 promotes the apoptosis of chronic myeloid leukemia cells,increases the expression of HSP60 and HSP70,and decreases the expression of HSP27.