[Abstract] Objective To evaluate the effect of anthracycline-induced cardiotoxity on left ventricular longitudinal systolic function by layer-specific strain technology in patients with breast cancer.Methods Sixty cases of breast cancer women patients using anthracycline-based chemotherapy were included, according to the different cycles of chemotherapy,the process were divided into four stages：the basic status before chemotherapy（LS0）,the second chemotherapy cycle（LSI）,the fourth chemotherapy cycle（LSII） and the sixth chemotherapy cycle（LSIII）.Two dimensional images were recorded from the apical four-chamber view,two-chamber view and long-axis view of the left ventricle during three consecutive cardiac cycles.Peak systolic longitudinal strain(LS)were measured in sub-endocardium,midmyocardium and subepicardium.Results The conventional echcardio graphic parameters had no significantly difference among the four stages(P > 0.05).In the four stages of chemotherapy cycle,LS of subendocardium was the highest,and subepicardium was the lowest(P < 0.05).LS of three views of endomyocardial in different stages had significant difference (P < 0.05) and they were reduced in the chemotherapy process,LSIII was the lowest. The difference of endomyocardial LS in different chemotherapy process all showed statistical significance(P < 0.05),but the difference between LSI and LS0 has no statistical significance.(P > 0.05).Conclusion The change of left ventricular myocardium longitudinal function in patients with breast cancer can be valued by the layer-specific strain technology,and the mainly dysfunction is in the subendocardium.