Objective To discuss the application of intramedullary interlocking nail in the treatment of femoral shaft fractures.Methods Retrospective analysis was given to 98 cases of femoral shaft fractures treated with intramedullary interlocking nails from January,1998 to December,2003.Results All cases were followed up,and 97 cases healed 13 to 24 weeks after operation(average 18.1 weeks).Joint function of coax,knee,ankle,recoveried.It bleeded 100~1200ml;Surgery time:50~140min,average 70.8min.In one case the far-end nail could not lock hole after operation,the host nail of one patient break three months later,far-end nail break in one patient four months later,no other complications was found.Conclusion Intramedullary interlocking nail is effective in the treatment of femoral shaft fracture.