Objective　To investigate the molecular mechanism of bone marrow mesenchymal stem cells (MSCs) in the treatment of injured cardiomyocytes and to explore the role of Wnt/β-catenin signaling pathway in this process. Methods After isolation, identification and culture for 72 hours, cardiomyocytes were divided into 3 groups: normal cardiomyocytes group (Group A), injured cardiomyocytes group (induced by 1 mg/L doxorubicin for 4 hours, Group B) and co-culture group (doxorubicininjured cardiomyocytes co-cultured with MSCs, Group C). After 72 hours of culture, apoptosis of cardiomyocytes was detected by flow cytometer, and the expression of β-catenin, c-Myc and p53 protein were tested by western blot. Results The apoptosis rates of cardiomyocytes in Group A, B and C were 0.74±0.65, 26.58±3.89 and 7.72±0.90, respectively, and the difference was significant (F=98.13, P<0.001). Through pairwise comparison, it was found that the apoptosis rate of cardiomyocytes in Group B was significantly higher than that in Group A and C (P<0.05). The results of western blot showed that the protein expression levels of β-catenin, c-Myc and p53 in Group B were significantly higher than those in Group C (P<0.01). However, in Group A, the protein expression of β-catenin, c-Myc and p53 could not be measured by western blot. Conclusions MSCs have significant anti-apoptotic effect on doxorubicin-induced cardiomyocyte injury and the molecular mechanism may related to the inhibition of Wnt/β-catenin signaling pathway.