Objective: In order to provide the scientific bias for clinical application, We analysed the biomechanic of self-designed 3 hollow compression screws+planting a piece of ilium (HSI) on femoral neck fracture (under the head). Method: Through experimental stress analysis on fresh cadaver femoral samples. Cure femoral neck fracture (under the head) with 3 hollow compression screws+planting a piece of ilium(HSI), compare this method with that by using 3 hollow compression screws only (HS) and observe the differences in biomechanical performance between these two internal fixation methods. Results Experimental results showed that there is no obvious difference in biomechanical performance between HSI method and HS method. 13 clinical practices have proved that to cure femoral neck fracture by using HSI method will not result femoral head necrosis(at least it has not happened yet). Conclusion To cure femoral neck fracture(under the head) by using HSI method is a very effective new method.