Objective To explore the clinical efficacy of external fixation combined with autogenous periosteal iliac bone for repairing cartilage injury of the talus. Methods The data of 18 patients with talus cartilage injury treated in Mianyang Central Hospital between January 2018 and January 2022 were retrospectively analyzed. All patients received autogenous periosteal iliac bone transplantation and external fixation brackets. The Visual Analogue Scale (VAS), joint range of motion, and the American Orthopedic Foot and Ankle Society (AOFAS) ankle posterior foot score were assessed before surgery and 6 months after surgery. The changes of cartilage damage of the talus on MRI before and after surgery were compared. The complications related to the operation were recorded. Results The patients included 5 males and 13 females, with an average age of (50.7±5.4) years. There were 6 cases injured on the left side and 12 cases injured on the right side. The Hepple’s classification was type Ⅲ in 8 cases and type Ⅳ in 10 cases. The average follow-up time was (17.6±8.2) months. The preoperative VAS score, ankle range of motion, and AOFAS score were 5.5±1.5, (48.0±10.5)°, and 54.9±11.1, respectively. Six months after surgery, the VAS score, ankle range of motion, and AOFAS score were 2.1±0.9, (64.8±7.8)°, and 82.6±8.7, respectively, and the differences from preoperative scores were all statistically significant (P<0.05). The preoperative MRI showed that the area of talus cartilage injury was (2.6±0.6) cm2, and the depth was (10.0±0.4) mm; the 1-year follow-up MRI showed that the area of talus cartilage injury was (0.6±0.2) cm2, and the depth was (5.5±0.3) mm, which statistically differed from those before surgery (P<0.05). By the last follow-up, no postoperative complications such as incision infection, bone graft fracture, and nonunion of the inner ankle were found. Conclusions Autogenous periosteal iliac bone graft can repair cartilage injury of the talus. External fixation stent provides early joint stability, avoiding uneven joint compression or joint impact.