To construct and apply a self-made tool in osteotomy in osteogenesis imperfecta. Prospective study on 33 patients with osteogenesis imperfecta at Military Hospital 7A - Military Region 7, from January 2012 to December 2016. Selected patients who were clinically diagnosed with osteogenesis imperfecta when meeting at least 2 of the 4 clinical diagnostic criteria of authors Greenspan A. and Beltran J. (2014) and selected a group of patients with indications for lower limb surgery to perform intervention and evaluate the results of internal fixation using self-made tool to treat lower limb bone deformities in patients with osteogenesis imperfecta. Patients who did not agree to participate in the study, or did not have enough medical records and X-rays, or had clinical and laboratory tests other than osteogenesis imperfecta were excluded from the study. There were 47 surgeries for 33 patients with 53 bone locations, including 6 patients who had 2 bone locations operated simultaneously in 1 surgery to treat bone deformities. The number of times it was necessary to enlarge or create the medullary canal was less in osteotomy in the femur than in osteotomy in the tibia. The average surgery time for the femur was 83.8 ± 7.6 min, and for the tibia was 86.3 ± 8.6 min. The average number of postoperative days was 9.9 ± 5.6 days. We have created a self-made tool for drilling and creating medullary canals in curved bones with bones that do not have medullary canals or are narrowed. This tool includes a V-shaped orientation frame and drill guide tube. Self-made tool when applied to bone surgery and bone fusion with 2 intramedullary nails to adjust lower limb bone deformities and prevent recurrent fractures to help patients improve their motor function and integrate into the community, effectively shortening surgery time, reducing blood loss, and helping to reduce the number of days after surgery.