Background and Aims: Previous studies have confirmed the anti-inflammation effect of bone marrow mesenchymal stem cell-derived exosomes (BMSC-Exo). We aimed to investigate the therapeutic effect of BMSC-Exo on diabetic kidney disease (DKD), as well as the underlying mechanisms. Methods: SD rats were induced by streptozotocin combined with a high-fat diet to establish a diabetes disease model. BMSCs-Exo were injected via tail veins at a weekly dose of 100 µg for 12 weeks. Pathological changes in the rat kidneys were evaluated using HE, Masson, and Periodic Acid-Schiff and immunohistochemical staining. TUNEL staining and western blot were used to evaluate the expression levels of apoptosis-related proteins in the rat kidney cells. The TNF-\alpha level was detected by PCR and NF-\kappaB (p65) by western blotting to examine the inflammatory responses in the renal tissue. Results: BMSCs-Exo significantly alleviated the renal structural damage and the distribution of apoptotic cells in diabetic rats. Furthermore, BMSCs-Exo increased the expression of pro-apoptosis protein Bax and decreased the expression of apoptosis-executing protein Cleaved Caspase 9 and Cleaved caspase 3. In addition, the transcription level of TNF-\alpha in kidney tissue and NF-\kappaB (p65) expression was also decreased through BMSCs-Exo treatment. Besides, the levels of glucose (GLU), creatinine (Cr), and burea nitrogen (BUN) in diabetic rats were decreased by the BMSC-Exo treatment. Conclusions: BMSCs-Exo may alleviate diabetic kidney damage by inhibiting apoptosis and inflammation.