Abstract Take a spline clutch which is in lifts’ power mechanism of high-rise for example， analyze the influencing factors in view of the spline transmission parameter design value uncertainty. The design variables are composed of the length of spline body, width, number of keys, inside and outside diameter . In strength in spline constraint conditions volume of the objective function is minimum established the mathematical model. Take advantage of the MATLAB software genetic algorithm to analyze the stress of the Spline clutch mechanism and carry on fuzzy optimization Calculation, Obtain a more reasonable set of spline parameters ，and help to improve the strength of the spline clutch. So as to improve the overall performance of the lifting mechanism.