In order to investigate the analytical calculation method of stress for circular holed infinite plate reinforced with rim bar, the average stress of rim bar region was regarded in the generalized plane stress state approximately and stress function was expressed as two undetermined holomorphic complex functions by complex analysis method in elasticity. The stress function as well as stress was solved through rim bar boundary condition, stress and displacement connection condition between rim bar and panel. Reinforcement coefficient of rim bar was proposed to describe the effect of the rim bar on alleviating stress concentration. Calculation examples demonstrate that the evaluation results of this proposed method have a good agreement with those of FEM, and that the reinforcement effect of the rim bar is obvious since the stress of circular holed infinite plate with rim bar is less than that of infinite plate absent of rim bar generally. Rim bar reinforcement effect is superior to annular additional thick plate in the case of maintaining the same volume of reinforcement components.