Objective To investigate the impact of high glucose on senescence of rat synovial mesenchymal stem cells（SMSCs）so as to provide a reference for risk management of SMSCs in the treatment of osteoarthritis in diabetic patients. Methods The rat SMSCs were divided into control group（physiological concentration of glucose with 5.5 mmol/L）and treatment group（high glucose with 25 mmol/L）. The senescence of rat SMSCs was detected， including cell proliferation，SA⁃β⁃Gal staining，mRNA expression of SASP（IL⁃6，MMP⁃13，TNF⁃α，CXCL1，IFN⁃β）， intracellular mitochondrial damage，p21 protein expression，and hyaluronic acid release. Results The high glucose medium did not affect the proliferation of SMSCs in the rats（P = 0.675）. Also，the high glucose medium enhanced the number of SA⁃β⁃Gal staining positive cells，the fragmentation of intracellular mitochondrial，and the mRNA expression of SASP，namely MMP⁃13（P = 0.011），TNF，TL⁃6，INFβ（P = 0.000），CXCL1（P = 0.003）. Meanwhile， the Western blot and ELISA results demonstrated significant down ⁃ regulated expressions of P21（P = 0.00）and hyal⁃ uronic acid（P = 0.002）. Conclusion High glucose induces senescence and biological function impairment of SMSCs in rats. The clinical effect of SMCSs in the treatment of osteoarthritis in diabetic patients remains to be confirmed.