To evaluate the efficacy of stromal vascular fraction (SVF) in treating osteoarthritis (OA). OA is a common degenerative disease, the most important manifestation of which is cartilage destruction and inflammation. The SVF is a mixed group of multiple cells extracted from adipose tissue with a certain ability to promote tissue repair. However, the biological safety and efficacy of human derived SVF in treating OA have not been confirmed. Seventy-six nude rats were used in this experiment. The rat OA model was constructed with anterior cruciate ligament transection (ACLT). After 4 weeks, SVF cells were injected into the joint cavity once. After 12 weeks, the experimental animals were sacrificed and decalcified sections were subjected to hematoxylin and eosin (H&E), safranine O staining, and AP-PAS staining and immunohistochemistry for inflammation markers. After surgery, the knee joint swells, pain intensifies, and the joint space narrows. The results of H&E, safranine O, and AP-PAS staining showed that the cartilage tissue was damaged in the ACLT-OA group and the treatment of SVF can reduce cartilage degradation. The numbers of ADAMTS-5-, MMP-13-, and IL-1-positive cells significantly decreased and type II collagen-positive cells were more frequently detected in the ACLT-OA group compared with that in the control group, the treatment of SVF can reduce inflammation. SVF cells can be safely used to treat OA and can both effectively reduce the progression of joint inflammation and promote cartilage regeneration.