Objective To investigate the expression changes of P-selectin（CD62P）in the doxorubicin （DOX）induced damaged cardiomyocyte line AC16 and atrial myocardial tissue from patients with heart failure(HF). Methods The AC16 cardiomyocyte line was cultured in vitro, and cardiomyocyte injury models with different degrees of damage were established using DOX at concentrations of 1μmol/L, 5μmol/L, and 15μmol/L. The experiment included control group (Ctrl) and myocardial injury model group (IM), which was further divided into mild (IM-Mi), moderate (IM-Mo), and severe (IM-S) subgroups. Immunofluorescence staining (IF) was used to identify the phenotype of AC16 cells, and the CCK-8 assay was employed to detect the proliferative activity of AC16 cells. Western blotting and immunohistochemical (IHC)staining were respectively used to determine the protein expression of CD62P in the AC16 cell line and human HF tissue samples. Additionally, ELISA was conducted to measure the expression levels of CD62P in the supernatant of AC16 cells with different degrees of DOX-induced damage and in the serum of patients with HF. Results In the AC16 cell line, the expression level of CD62P increased with the elevation of DOX concentration （P<0.05）, showing a dose-dependent upward trend. The positive rate of CD62P in the human HF group was significantly higher than that in the control group; Moreover, the expression level of CD62P increased as the severity of HF worsened (P<0.05). The detection result of CD62P in serum were consistent with the expression trend of CD62P in tissue. Conclusion The expression levels of CD62P in local tissues and peripheral serum are positively correlated with the degree of myocardial injury, suggesting that CD62P may serve as a potential biomarker for evaluating the progression of heart failure.