Although doxorubicin (DXR) is an effective antineoplastic agent; the serious cardiotoxicity mediated by the production of reactive oxygen species has remained a considerable clinical problem. Our hypothesis is that tanshinone IIA sodium sulfonate (TSNIIA-SS), which holds significant affects on cardioprotection in clinic, protects against DXR-induced cardiotoxicity. In vitro investigation on H9c2 cell line, as well as in vivo study in animal model of DXR-induced chronic cardiomyopathy were performed. TSNIIA-SS significantly increased cell viability and ameliorated apoptosis of DXR-injured H9c2 cells using CCK-8 assay and Hoechst 33342 stain respectively. Furthermore, the cardio-protective effects of TSNIIA-SS were confirmed with decreasing ST-interval and QRS interval by electrocardiography (ECG); improving appearance of myocardium with haematoxylin and eosin (H&E) stain; increasing myocardial tensile strength using tension to rupture (TTR) assay and decreasing fibrosis through picric-sirius red staining comparing with those receiving DXR alone. These data have provided the considerable evidences that TSNIIA-SS is a protective agent against DXR-induced cardiac injury.