Objective To investigate the effects of stress changes by using different internal fixation methods in femoral neck fracture in order to find out the most optimal one with sound biomechanical principles before clinical application. Methods Pro/ENGINEER software was used to create a solid model, which was subsequently input into ANSYS 5.7 to establish Finite Element Analysis (FEA) model. A femoral neck fracture with Pauwel's angle of 50° and fixed with a single screw was used to find out the best fixation angle with sound biomechanical principle. Different internal fixations with 2 or 3 screws were then used to find the one with best fixation quality at this best fixation angle. Results When fixation was made for single screw at 50°, all evaluated parameters reached their lowest value, which suggested the optimal screw fixation angle. When 2 or 3 screws were used for fixation, the fixation with two level ones revealed overall the most inferior mechanical stability; two vertically placed screws for fixation showed the lowest anti-torsional property; the fixation with two obliquely inserted screws or combination of three screws provided better mechanical stability. After balancing many factors and from the clinically practical point of view, Single screw fixation was found to be technically simple and also provided reasonable good fixation effects. Conclusion Results of FEA analysis suggested that the difference in screw fixation angles and in way of combined use of screws might have important influence on biomechanical stability of femoral neck fracture fixation.