Objective　 To provide anatomical basis for the design of a new internal humerus fixator and its application.　Methods　40 sides of adult upper limb specimens with were dissected, the course of the axillary nerve, radial nerve was observed and the distance from them to the related osseous landmarks were measured. Meanwhile, 30 adult dry humerus specimens were selected, the related diameter and circumference of the upper humerus were measured and the optimal radian was calculated.　Results　The maximum length of the humerus was (30.21±0.22) cm; The greater tubercle to the axillary nerve length was (5.48±0.09) cm; The greater tubercle to deltoid tuberosity length was (12.80±0.13) cm; The nearest end of humerus to the entry and exit of humerus muscle tube were (16.10±0.27) cm and (21.04±0.26) cm, respectively; The best radian of upper humerus was (3.90±0.03) rad.　Conclusion　When the radian of arched segment reach 3.9 rad, the new humerus internal fixation can achieve very good adherence as well as reducing the incidence of the radial nerve injury effectively.