Objective To evaluate the clinical effect of electromagnetic navigation system to locate the distal locking screw of tibia intramedullary nail.Methods From February 2010 to December 2016，79 cases of tibia shaft fractures requiring treatment with intramedullary nailing were selected and divided into the navigation group and free hand locking group according to intramedullary nail locking methods.Forty-four cases in navigation group used an electromagnetic navigation system to lock the distal end of the intramedullary nail

while 35 cases in free hand locking group used a freehand technique.The intraoperative X-ray exposure time

distal locking time

healing time，and the success rate of onetime distal locking were recorded compared between two groups.Results The average time of diatal locking using electromagnetic navigation technology was less than that of the free hand locking group

and the exposure time of fluoroscopy was also reduced

the differences were significant（P<0.05）.There was no difference in fracture healing time between the two groups（P＞0.05）

onetime success rate of navigation group was 100%

which was higher than 37.34% of the free hand locking group

the difference was significant(P<0.05).Conclusion Compared with free hand technology

the advantage of using electromagnetic navigation system to lock the distal nail of tibia intramedullary nail is high efficiency

short locking time and no radiation.