To evaluate the effects of simvastatin on the degeneration of cartilage and subchondral bone in a mice model of osteoarthritis (OA) induced by obesity. Thirty male 3-month-old C57BL/6J mice were randomized into three groups: mice with normal diet + vehicle (distilled water) (Control), mice with High-fat diet + vehicle (HFD), mice with HFD + Simvastatin (HFD+S). HFD+S group were treated with simvastatin (10 mg/kg/day) for 12 weeks. The pathology of OA was assessed by histomorphology analyses, immunohistochemistry, micro-computed tomography, and enzyme-linked immunosorbent assay. Histomorphological analysis revealed that OA was significantly exacerbated by the HFD-induced obesity and markedly alleviated by the simvastatin intervention. In details, simvastatin ameliorated the abnormal metabolic status and cartilage lesions, significantly increased aggrecan and collagen-II expression and decreased the expression of MMP-13 and leptin in cartilage. Furthermore, the results of micro-CT analysis revealed that the HFD+S group exhibited higher BMD, BV/TV, and Tb.N values but a lower Tb.Sp value than that of the HFD group. Serum glucose, leptin, and IL-1β concentrations were significantly correlated with the OARSI score. Histomorphological analysis revealed that OA was significantly exacerbated by the HFD-induced obesity and markedly alleviated by the simvastatin intervention. In details, simvastatin ameliorated the abnormal metabolic status and cartilage lesions, significantly increased aggrecan and collagen-II expression and decreased the expression of MMP-13 and leptin in cartilage. Furthermore, the results of micro-CT analysis revealed that the HFD+S group exhibited higher BMD, BV/TV, and Tb.N values but a lower Tb.Sp value than that of the HFD group. Serum glucose, leptin, and IL-1β concentrations were significantly correlated with the OARSI score. The HFD-induced obesity aggravates articular degeneration and deterioration in subchondral bone, which could be improved by the intervention of simvastatin, suggesting that simvastatin may be a potential candidate for amelioration of the progression of obesity induced-OA. Obesity has certain influence on OA due to its induction effect of chronic inflammation and abnormal metabolic syndrome. In this study, we further studied the pathology of obesity induced OA in mice. Simvastatin has potential therapeutic effects on OA. However, it is currently unknown whether the simvastatin intervention can amplify the remission of the pathological state of OA induced by obesity. Our study confirmed for the first time that simvastatin intervention has a strong effect in protecting obese mice from joint damage. [ABSTRACT FROM AUTHOR]