〔Abstract〕 To investigate the effect of tibial intramedullary nailingviasuprapatellar and infrapatellar approaches on knee function after tibial shaft fracture. 85 cases of tibial shaft fractures were treated with tibial intramedullary nailing, including 40 cases of suprapatellar approach(suprapatellar approach group) and 45 cases of infrapatellar approach(infrapatellar approach group). Range of motion(ROM) and Hospital of Special Surgery(HSS)coring system of knee joint were evaluated 12 months after operation. There was no significant difference in operation time and intraoperative blood loss between the two groups. 12 months after operation, the total HSS score, pain score and functional activity score were(97.78±4.14),(28.44±2.78) and(21.47±2.50) for suprapatellar approach group respectively while they were(97.11±5.90),(29.13±1.92) and(21.73±1.26) for infrapatellar approach group respectively. There was no significant difference between the two groups. In the ROM score of knee joint, the range of motion of the infrapatellar approach group(17.47±1.06) was larger than that of the suprapatellar approach group(16.85±1.49)(P=0.023). Tibial intramedullary nailingviasuprapatellar approach and infrapatellar approach can achieve good results in the treatment of tibial shaft fractures, but the range of knee flexion and extension in the infrapatellar approach group is larger than that in the suprapatellar approach group, so the suprapatellar approach needs further study to reduce the damage to quadriceps femoris.