Anthracyclines have been one of the most important therapeutic methods in breast cancer therapy for decades. However, serious long-term toxicities, especially cardiotoxicity limits the continuous usage of anthracyclines, hence affects long term prognosis. Early detection of myocardial dysfunction during treatment is critical but challenging. Two-dimensional speckle tracking echocardiography (2D-STE) is a non-Doppler technique that can assess deformation and strain by tracking displacement of acoustic markers in the myocardium. This study aims to compare the sensitivity and precision between 2D-STE and traditional echocardiography on monitoring the left ventricular function in patients with breast cancer after anthracyclines therapy, which is the key indicator for evaluating myocardial changes. Thirty-three patients with breast cancer were recruited from February 2019 to December 2019. All patients were treated with 4 cycles anthracycline. 2D-STE and conventional echocardiography were performed on each patient. Two-dimensional echocardiographic examination was used to collect data interventricular septum diameter (IVSD), end-diastolic left ventricular posterior wall diameter (LVPWD), left ventricular end-diastolic diameter (LVEDD) and left ventricular systole on the parasternal left ventricular long axis view. The final diameter (left ventricular end-systolic diameter [LVESD]) and the left ventricular short axis shortening rate (LVFS) was measured by M-type. The two-plane Simpson's method was used to measure left ventricular end-diastolic volume (LVEDV) and end-systolic volume (left ventricular end-systolic volume [LVESV]) to obtain left ventricular ejection fraction (LVEF). Two-dimensional speckle tracking imaging technical indicator includes left ventricular global longitudinal strain (LVGLS), subendocardial myocardial longitudinal strain (LVGLS-Endo) and epicardial myocardial longitudinal strain (LVGLS-Epi). The correlation between 2-dimensional speckle tracking imaging and conventional ultrasound parameters were analyzed. Compared with baseline (T0), the systolic function parameter LVEF was significantly changed after four cycle chemotherapy (T4) (P < .05). However, the conventional echocardiographic parameters including IVSD, LVPWD, LVEDD, LVESD, LVEDV, and LVESV were not statistically significant (P > .05). Meanwhile, the two-dimensional strain parameters LVGLS, LVGLS-Endo, and LVGLS-Epi were statistically significant after T2 and T4 cycle chemotherapy (P < .01).The two-dimensional strain parameter GLS has higher accuracy and sensitivity for monitoring left ventricular insufficiency caused by anthracycline therapy when compared with traditional echocardiography.