Objective  To measure the distance between the lateral compression Ⅱ (LC-Ⅱ) screw guide needle and the surrounding important structures around the anterior inferior iliac spine in pelvic fractures and to locate the needle point, so as to provide anatomical reference for clinical nail placement. Methods  Totally 40 adult gross specimens of embalming were implanted with LC-Ⅱ screw guide needle under the surveillance of C-arm machine, and the specimens were dissected. The shortest distance between the insertion point and the lateral femoral cutaneous nerve, femoral nerve, femoral artery, femoral vein, anterior superior iliac spine and inguinal ligament was measured. The triangle was constructed between the insertion point, anterior superior iliac spine and inguinal ligament, and the exact location of the entry point was calculated. Results  The average distance between the insertion point of the male needle and the femoral vein was（50.67±7.29）mm> the anterior superior iliac spine (43.83±7.58) mm> the femoral artery (38.35±6.63) mm> the femoral nerve (31.17±1.67) mm= the inguinal ligament (28.69±6.59) mm> the lateral femoral cutaneous nerve (7.98±3.81) mm. The mean distance between the insertion point of the female needle and the anterior superior iliac spine was (45.28±7.07) mm= femoral vein (43.72±6.89) mm> femoral artery (33.76±6.33) mm> femoral nerve (25.66±6.46) mm= inguinal ligament (23.22±5.00) mm> lateral femoral cutaneous nerve (8.97±4.76) mm. The projection distance of the entry point was 31.77mm for men and 38.41mm for women. The Angle b was 42.81°for men and 31.71°for women. Conclusion  The lateral femoral cutaneous nerve is most vulnerable to injury when LC-Ⅱ screw is inserted, and the risk of injury has nothing to do with sex. The insertion point positioning method  a and b made LC-Ⅱ screw placement quickly, safely and accurately, and reduced fluoroscopy time and frequency.