The arch dam is a kind of massive water retaining structures pouring with concrete.The overall failure mechanism and corresponding analyzing criterion are key concerning issues in dam engineering field.In this paper, the energy evolution of arch dam in the failure process is studied firstly, that it can be decomposed as dissipationenergy accompany with concrete damage, and elastic strain energy absorption and releasing during elastic deformation.Then, an evaluation criterion for failure analysis of concrete arch damsisestablished based on elastic strain energy.Afterwards, an orthotropic damage constitutive model for dam concrete is proposed, and the numerical simulation method of which is established for structural failure analysis.Numerical simulations show that the value of elastic strain energy in elements,rise with an increase of the overload safety coefficient and finally converge to the material surface energy, at which time the local plastic damage area develops rapidly and finally leads to cracking failure of structures.The proposed failure analysis criterion for concrete dams under integrated loads is suitable for analyzing dam instable failure, which is of great operability and engineering application value in the future.