Osteosarcoma, a highly aggressive bone cancer, primarily affects adolescents and is frequently treated with conventional chemotherapy, such as doxorubicin (DOX). However, the efficacy of DOX is often limited by severe side effects and drug resistance. This study investigates the synergistic effects of static magnetic fields (SMF) and DOX on G292 osteosarcoma cells and HFF normal fibroblasts. Cell viability was assessed using the MTT assay, intracellular reactive oxygen species (ROS) levels were quantified via DCFDA staining and flow cytometry, and iron and calcium homeostasis were analyzed using ICP-OES. Apoptosis and necrosis were determined through Annexin V-FITC/PI staining. Results demonstrated that the combination of SMF and DOX significantly reduced G292 cell viability compared to DOX alone, with IC50 values decreased from 3.2 µM (at 3 mT, p < 0.01) to 0.8 µM (at 24 mT, p < 0.001) at 24 h. Apoptosis rates increased from 8.12% with DOX alone to 16% with SMF + DOX. While DOX alone elevated ROS levels by 59.15% in G292 cells, SMF further amplified apoptosis by enhancing ROS generation and disrupting iron and calcium homeostasis. These findings suggest that SMF enhances DOX-induced cytotoxicity in osteosarcoma cells by promoting ROS production, altering metal ion homeostasis, and increasing apoptosis. SMF represents a promising adjuvant therapy for osteosarcoma treatment, though further in vivo studies are necessary to optimize treatment parameters and evaluate clinical applicability.