PURPOSE: The purpose of this study was to confirm recovery effects of exercise rehabilitation according to the cast duration after achilles tendon repair. METHODS: It was divided by 3, 6, 8 weeks of cast immobilization duration and this is a case study comparing the difference in recovery speed depending on the cast duration. Total cases were six and all patients were treated the same for two weeks after surgery. All physical examination checked at 12week, 14week, 16week and 18week. Test items were included swelling, visual analysis score, range of motion, functional movement and questionnaire scale. RESULTS: As shown in the study, it was found that 3 weeks of cast immobilization and rehabilitation exercise after Achilles tendon repair were almost possible after 14 weeks of surgery, and 16 weeks later, dynamic exercises such as jogging were possible. However, in the case of cast immobilization for 6 weeks and 8 weeks, daily life was not possible until 16 weeks, and jogging was not possible until 18 weeks. CONCLUSIONS: If you want to return to your daily life quickly after Achilles surgery, Three weeks of postoperative cast fixation and four weeks of rehabilitation exercise have been shown to shorten the recovery period than six or eight weeks of cast fixation.