To develop the cup-shaped flexible gear of harmonic reducer,APDL language of ANSYS is used to model its parametric interface,which is used to analyze the stress of flexible gears from type 25 to 60 under the effect of wave generator.The results,consistent with the experiential formulas,show the validity of the model and depict the relation between the flexible gear’s maximum equal stress and the type of flexible gear.To the specific type of 32,the effects of variations of key structure parameters,including cylinder length,gear thickness,smooth cylindrical wall thickness,tooth width,and fillet radiuses of three flexible gears,on maximum equal stress of flexible gear and smooth cylinder,are analyzed,which provides the basis for structural parameter optimization.Under the coupling effect of heat and structure,temperature variation effect on stress of flexible gear is analyzed with simplified model,which provides the basis for research failure of flexible gear in the high and low temperature environment.