Numerical analysis for the load/deflection behavior of thin-web plate girders have been studied in this paper using a finite element program. An analytical approach presented in literature was discussed, and hence, it was used to calculate the load/deflection values in prebucking and post buckling stages. The validated finite element model is used to discuss the meaningful of the analytical approach. The effect of different parameters on load-deflection curves is proposed. Stiffener thickness (), end post type (no end post (NEP), rigid end post (REP), and non-rigid end post (NREP)) and end distance (e) are the main parameters considered in this paper. The analytical approach estimates well the load/deflection behaviors of REP and NREP plate girders with (a/hw < 2.2). On the other hand, the analytical approach can't estimate
either for the shear strength or the deflection of NEP plate girders.