In this research, a nonlinear finite element model developed to investigate the behavior and ultimate load capacity of unbonded post-tensioned one-way concrete slab panel. The numerical treatment adopted by finite element ANSYS software has been carried out on two different one-way concrete slabs chosen from previous available experimental study in order to evaluate their results. Mode of failure and the loaddeflection relationship are presented for two cases. A parametric study was conducted to study the effects on the global structural behavior due to the effect of concrete compressive strength, effect of effective prestressing stress, effect of prestressing (post-tensioning) technique, types of loading, effect of tendon profile, effect of tendon bonding, effect of span to depth ratio of concrete slabs.