Research conclusions:(1) On consideration of the structure on the arch，the minimum eigenvalue buckling in the analysis result was 13.477，and the eigenvalue buckling of the bare arch in the analysis result was 6.663．Both of them were bigger than 4 and 5 stipulated in the specification．The arch rib met the requirements of the stability inside and outside of the cross － section．(2) The minimum ultimate bearing capacity of the arch bridge in the analysis result was 2.252，and it showed that under the influences of the double nonlinearities and the initial defects of the structure，the safety factor of the bridge under main working conditions was 2.252，meeting the requirements of no less than 2 for the elastic － plastic stability safety factor on consideration of the nonlinear effects of the structure，and the structural design was reasonable．(3) The structures on the arch like the pier columns had the big effect on the stiffness of the bridge，while they had small impact on the ultimate bearing capacity of the arch．(4) The eigenvalue buckling in the analysis result was of a nonconservative calculation result． In the actual process of designing an arch bridge，the influences of the double nonlinearity and initial defects of the structure on the ultimate bearing capacity had to be considered． And the methods introduced in this paper could be as the reference to the similar works．