A three-year-old child with a broken leg can heal from three weeks to a month, and for a month and a half. However, the prerequisite is systematic treatment throughout the process, because the fracture only has a chance to heal if the fracture is fixed together, and without good fixation the fracture will heal very slowly and may not heal if it is repeatedly moved. Whether the fracture is protected by skin traction or external fixation in a cast or even surgical treatment of the fracture, it is a prerequisite for the entire fracture to heal within a specific period of time. With these systematic treatments, the fracture will heal in three weeks to one month, and at a later stage, functional rehabilitation will be carried out slowly, and the child will be instructed to gradually return to normal activities on the floor. This step is also very critical not to postpone, otherwise the whole recovery exercise time will be delayed.