Abstract: Effects of plasma configuration and effective ion charge (Z_eff) with neutral beam heating on EAST are studied with guiding center codes ORBIT and TRANSP/NUBEAM. The resultes show that the fast-ion loss (including prompt and ripple losses) decreases as the distance between the last closed flux surface and the outer vessel wall in the mid-plane(gapout) and the toroidal magnetic field increases in the magnetic configuration. As a result the beam-ion confinement are enhanced and the heating efficiency is increased. Moreover, as the background plasma impurities increase, i.e., Z_eff increases the beam-ion loss increases, resulting in the reduction of beam-ion heating efficiency. Thus, choosing appropriate magnetic configuration and reducing the background impurity content enhance the fast-ion confinement and improve the beam heating efficiency.