Abstract: [Objective] To introduce the surgical technique and preliminary results for correcting the malunion of calcaneal fracture by lateral four-knife osteotomy. [Method] From January 2016 to October 2019, 19 cases of calcaneal fracture malunion were corrected by lateral four-knife osteotomy. The patient took the contralateral lateral position, and exposed the calcaneus through an inferior malleolus transverse incision. According to the preoperative evaluation, a four-knife osteotomy was performed, a multi-planar sagittal osteotomy was used to restore articular surface flatness, correction of deformities, and bone grafting in the bone defect area, Fix the osteotomy with the calcaneal locking plate, and perform Achilles tendon lengthening if necessary. [Results] All the 19 patients were successfully operated without serious complications. The follow-up time was 9-30 months. After the operation, the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Score, Visual Analogue Scale for Pain (VAS), calcaneal height, width, B?hler angle and Gissane angle were significantly improved, and the difference was statistically significant compared with preoperatively ( P<0.05), there was no significant difference between the postoperative imaging measurement of the calcaneus length and the preoperative comparison (P>0.05). [Conclusion] Lateral four-knife osteotomy is an effective method for the treatment of calcaneal fracture malunion. It can significantly correct calcaneal deformity, restore calcaneal biomechanical relationship, and improve the patient's foot symptoms.