To investigate the role of chamagogic polysaccharides (polysaccharides of Brassica rapa L., BRPs) against doxorubicin (DOX) cardiotoxicity and related mechanisms, H9c2 cells were selected for the study, and the effects of BRPs on DOX induced damage in H9c2 cells were detected by cell counting kit-8 (CCK-8); H9c2 cells were divided into the control group, the model group, and the drug group (0.5-3 mg·mL^-1); the control group was cultured under normal conditions, and the remaining groups were induced for 24 h by 1 μmol·L^-1 DOX after treatment. Apoptosis was detected by flow cytometry; the levels of lactate dehydrogenase (LDH), superoxide dismutase (SOD) and malondialdehyde (MDA) were measured in each group; intracellular reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) were detected. Western blot was used to detect the expression of proteins related to the apoptosis and transcription factor NF-E2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway. Compared with the control group, DOX-induced H9c2 cell injury was characterized by decreased cell viability, increased apoptosis, elevated LDH and MDA levels, decreased SOD activity, significantly increased ROS levels, and significantly decreased MMP; the level of B cell lymphoma-2 (Bcl-2) protein decreased, and the level of Bcl-2 associated X protein (Bax) increased significantly; In the model group, the expression levels of Nrf-2, HO-1, quinone oxidoreductase 1 (NQO1) were reduced, and the expression levels of Kelch-like ECH-associated protein 1 (Keap1) and phosphorylated p38 mitogen-activated protein kinase were significantly increased, Moreover, BRPs (0.5-3 mg·mL^-1) increased the protein expression levels of Nrf2, HO-1, and NQO1, and decreased the levels of Keap1 and phosphorylated p38 mitogen-activated protein kinase. In summary, the ability of BRPs to protect H9c2 cells and inhibit apoptosis may be related to their regulation of the Nrf2/HO-1 pathway to antagonize oxidative stress.