Abstract: In this paper it was presented that Second-order analysis method on buckling of arches The geometric nonlinear finite element equation has been developed according to the theory of finite deformation and has been solved using the self correting method Various methods of solving nonlinear differentiating equation and selecting loading step have been discussed The C method developed by author which can automatically select loading step has been introduced numerical examplas sho.wed that the mathod and program are correct.