Objective To observe the clinical outcomes of the treatment of comminuted femoral shaft fractures with combination of intramedullary interlocking nail and shape memory sawtooth-arm block hoop internal fixator. Methods 35 cases of comminuted femoral shaft fractures were treated with combined use of intramedullary interlocking nail and shape memory sawtooth-arm block hoop internal fixator. Of the 35 cases, 25 were type B and 10 type C according to AO classification. 1 case had bilateral femoral shaft fracture of type B. Results All the fractures were followed up for 12 to 24 months (averaging 18.5 months). By second attention, all the fractures healed except 1 case who had to undergo secondary surgery because his shape memory sawtooth-arm block hoop internal fixator had dropped. The intramedullary interlocking nails were taken out 18 to 24 months postoperatively. The excellent rate was 98.2%according to Klemm grading system. Conclusion In treatment of comminuted femoral shaft fractures, the combined use of intramedullary interlocking nail and shape memory sawtooth-arm block hoop internal fixator can take advantages of the 2 devices so as to secure anatomic reduction and reliable fixation.