Objective?To study the effects of knee arthroscopic microfractures on knee joint function and synovial fluid inflammatory factors in patients with knee cartilage injury. Methods?150 cases of knee cartilage injury patients admitted to Jilin People’s Hospital from June 2019 to June 2020 were selected and grouped according to the random number table method. The control group (75 cases) underwent arthroscopic joint debridement, and the observation group (75 cases) underwent knee arthroscopic microfracture. The clinical efficacy of the two groups at 6 months after surgery, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), matrix metalloproteinase-13 (MMP-13) in the synovial fluid before and 2 weeks after surgery, New York Hospital for Special Surgery (HSS) score, Tegner activity scale before and 6 months after surgery and postoperative complications were compared between the two groups. Results?The total clinical effective rate of the observation group was higher than that of the control group; Compared with before surgery, the inflammatory factors in the synovial fluid of the two groups decreased at 2 weeks after surgery, and the knee joint function scores increased at 6 months after surgery, the improvement of the observation group was better than that of the control group (all P ?0.05). Conclusion?Knee arthroscopic microfractures in patients with knee cartilage iinjury can improve the therapeutic effect, improve knee joint function, reduce inflammation in the articular fluid, promote cartilage repair, and with good security.