BACKGROUND The tibia is one of the most vulnerable to trauma in human long bones, accounting for 13.7% of the total body fracture, with a higher proportion of men than women of approximately 4:1. Most of the occurrences of tibial fractures (distal articular surface) are mainly caused by high violence trauma. In recent years, with the rapid development of China's industry, the incidence of tibial fractures has shown an increasing trend. AIM To investigate the effect of internal fixation of tibial fractures per suprapatellar approach on fracture union and knee function recovery. METHODS A total of 100 patients with tibial shaft fracture underwent operations in our hospital were selected as the study subject, and they were divided into a suprapatellar group (suprapatellar approach for intramedullary nail fixation) and subpatellar group (suprapatellar approach for intramedullary nail fixation) according to prospective randomized study, each group had 50 cases. The operative time, blood loss, X-ray irradiation times, fracture healing time, postoperative knee pain score, knee Lysholm score, and surgical complication rate were compared between the two groups. RESULTS There were no significant differences in operative time, blood loss, and fracture healing time between the suprapatellar and subpatellar groups (P>0.05). X-ray irradiation times in the suprapatellar group were lower than those in the subpatellar group (P<0.05). Visual analog scale (VAS) scores were compared 1d-14d after the operation, and the suprapatellar group had lower VAS scores than the subpatellar group (p <0.05). The Lysholm score was used to evaluate knee function 6 months postoperatively, and swelling and pain scores were higher in the subpatellar group than in the suprapatellar group (p <0.05). However, there were no significant differences in the knee Lysholm total score between the two groups (p >0.05). There were no significant differences in postoperative complications between the two groups (p >0.05). CONCLUSION Suprapatellar in