The flexible hinges in the compliant mechanism,when the cyclic loading with continuous and variable loads,are easily to induce the fatigue crack initiation in its thinnest place due to stress concentration. It ultimately causes fatigue failure in the flexible hinges. Using the elliptical hinge as the research object,this paper analyzed the characteristics of the maximum applied stress in the thinnest place of flexible hinges by using Taguchi Method. Orthogonal experiments were performed upon finding out the controllable factors and noise factors affecting the maximum stress. Sensitivity analysis based on Orthogonal experiments was applied loading to quantitatively analyze the effect of each design variable parameter on the maximum stress. The calculation showed that the change of the maximum stress depends on several design variables parameters,and the geometric parameter plays an important role. This method does not depend on optimization algorithm,can be employed for sensitivity analysis of discrete,non-differential or implicit-expression structures,and provides favorable reference to the robust design of the flexible hinges by improving its fatigue life.