In order to study the nonlinear stability of the long-span concrete arch Bridge with embedded framework, based on the Tian'e Longtan Bridge, an analysis was carried out, and the influence of various factors was discussed. The FE (finite element) method considering dual nonlinearity was used. An elaborate FE model of the main arch was built, and loads applied to it were increased gradually until it met the ultimate capacity. In the analysis, different working conditions are set for various factors such as nonlinear factors (geometrical nonlinearity and material nonlinearity), initial imperfection, and vehicle load distribution methods. By comparing the nonlinear stability factors of different working conditions, the importance of the influencing factors to the analysis is discussed. The analysis found that the analysis results considering only geometric nonlinearity or only material nonlinearity are very different from the one considering dual nonlinearity; the nonlinear stability factor of model considering initial imperfection is slightly lower than that leaving it out; among various vehicle load distribution methods, the highest nonlinear stability factor comes from the one with full-span distributed load, while the lowest comes from the one makes the largest bending moment in arch crown, but the difference is not significant. It can be concluded that the influence of geometric nonlinearity and material nonlinearity cannot be ignored; the nonlinear stability of the bridge is mainly controlled by the dead load, other factors such as initial imperfection and vehicle load distribution methods have little impact on the analysis.