Objective To evaluate left ventricular (LV) systolic function and LV dyssynchrony in patients with anthracycline chemotherapy by two-dimensional speckle tracking imaging (2D-STI) for the investigation of the value of 2D-STI in early diagnosis of myocardial toxicity with anthracycline chemotherapy. Methods 40 patients diagnosed with breast cancer and epirubicin chemotherapy were prospectively enrolled. The strain parameters by EchoPAC analysis software included global longitudinal strain (GLS), GLS of endocardial and epicardial layers (endoGLS and epiGLS) and global circumferential strain (GCS), GCS of endocardial and epicardial layers（endoGCS and epiGCS), global radial strain (GRS) at baseline (T0), after the first cycle (T1) and after the second cycle (T2) of chemotherapy. At the same time, the time of the 18 segments to maximal systolic longitudinal, circumferential, radial strain (Tssl, Tssc, Tssr) were measured. The longitudinal, circumferential, radial segmental standard deviation (Tssl-SD, Tssc-SD, Tssr-SD) and the maximal difference of Tssl, Tssc, Tssr (Tssl-Dif, Tssc-Dif, Tssr-Dif) were calculated; the sum of the difference between the longitudinal, radial and circumferential strain peaks and the final strain of the 18 segments was measured, which is longitudinal, radial and circumferential strain delay indices (LSDI, CSDI, RSDI). Results GLS, endoGLS, endoGCS at T2 were significantly lower than those in T0 (p2＜0.05, all).while Tssl-SD and LSDI in T2 were significantly increased comparing to those in T0 (p2＜0.05, all). Conclusions With accurate assessment of endoGLS and Tssl-SD for the analysis of LV global systolic function and dyssyncrony, the myocardial toxicity at early stage can be detected sensitively by 2D-STI in patients with anthracycline chemotherapy.