To retrospectively study medium term follow up outcomes effects of effect of bio-lengthend stem hemiarthroplasty in the treatment of unstable osteoporotic intertrochanteric fractures in elderly patients. Total of 32 elderly patients with the osteoporotic intertrochanteric fractures were treated with bio-lengthend stem hemiarthroplasty from Jan. 2016 to Jan. 2019 including 14 males and 22 females, aged from 85 to 95 years old with an average of (89.5±4.5) years old. According to classification of Evans, there were 12 cases with type Ⅲ, 11 with type Ⅳ and 9 with type Ⅳ. The time from injury to operation ranged from 0.5 to 9 days with an average of (4.5±3.9) days. The operation time, blood loss and postoperative complications were analyzed. Functional outcome was assessed by Parker Palmer mobility score(PPMS) and Harris hip score. Four patients died within one year after operation, and the mortality was 12.5%. The follow up time for the rest 28 patients ranged from 24 to 60 months with an average of (28.5±4.5) months. The mean operative time was (54.2±22.5) min;the mean blood loss (hidden blood loss+obvious blood loss) was (450±140) ml;the first weight bearing was (3.35±1.35) days. No perioperative death occurred. PPMS were(6.63±1.25), (6.94±1.18), (7.11±0.83), (7.32±1.11) and Harris scores were(67.85±6.19), (71.42±5.57), (73.41±5.62), (77.32±5.24) respectively at 1, 3, 6 months and the final follow-up after operation. There were no significant difference in PPMS and Harris score at 1, 3, 6 months after operation and the final follow-up(P>0.05). There were no complications such as joint dislocation and prosthesis loosening occure at the final follow-up. On the premise of strictly mastering the case selection criteria, the bio-lengthend stem hemiarthroplasty in the treatment of unstable osteoporotic intertrochanteric fractures in elderly patients has a satisfied medium term follow-up outcomes. It can restore hip function in the early stage and improve the quality of life of patients.