Abstract:[Objective] To test a domestic visual electromagnetic navigation system by observing its effect on distal locking screw place-ment of intramedullary nail in the femur model. [Method] Based on the measurement principle of coordinate position of the object measur-ing the change rate of three mutually perpendicular magnetic fields, this visual electromagnetic navigation system was developed by combin-ing positioning coil and reluctance sensor. Thirty artificial femur models were randomly divided into navigation group and conventionalgroup, with 15 in each group. In both groups, intramedullary nail with handles were inserted into the femur model. In the navigation group,the visual electromagnetic navigation system was used to assist the 3 locking screws placement at the distal end of the intramedullary nail,while in the conventional group, a conventional mechanical guider was used to assist the 3 locking screws placement at the distal end. Thecontinuous insertion time of 3 screws in two groups and the success rate at the first placement were recorded and compared. [Results] Theinsertion time of the first, second and third screws in the two groups increased in sequence, with statistical significance (P＜0.05). The navi-gation group proved significantly superior to the conventional group in terms of continuous insertion time of the first screw [(156.3±14.8) secvs (266.8±31.2) sec, P＜0.05], the second screw [(230.7±17.1) sec vs (318.1±32.2) sec, P＜0.05], and the third screw [(306.5±20.8) sec vs(408.6±27.7) sec, P＜0.05]. However, there was no significant difference in the success rate at the first placement between the two groups(P＞0.05). [Conclusion] This visual electromagnetic navigation system is accurate in positioning, and does significantly shorten the time ofdistal locking screw placement of intramedullary nail in femur model compared with the mechanical guider.