Objective To investigate the effect of Life′s Simple 7（LS7）intervention on chemotherapy⁃ related cardiovascular system damage in HER2 positive patients with breast cancer after radical surgery. Methods A total of 120 HER2 positive patients who received standardized chemotherapy for breast cancer were randomly divided into control group and LS7 group. The control group was addressed with standard chemotherapy scheme，and LS7 group was treated with LS7 intervention for 12 months on the basis of the control group. The improvement effect of cardiovascular system damage in the two groups was evaluated by comparing the degree of cardiovascular system damage，anxiety，depression，and quality of life before and after treatment. Results Compared with the control group，the LS7 group had better overall LS7 score and 7 cardiovascular health indicators（P < 0.05）. The LS7 group had higher LVEF（P < 0.05），lower NT⁃proBNP（P < 0.05），lower anxiety and depression score（P < 0.05）， and higher quality of life score（P < 0.05）. Conclusion LS7 intervention can significantly reduce chemotherapy⁃ related cardiovascular system damage in HER2 positive breast cancer patients and improve the mental health and quality of life of breast cancer patients，which is worthy of clinical promotion.