A behavior analysis on reinforced concrete frame structures under near-fault velocity-pulse ground motions is numerically performed by using simulation software and finite element method (FEM). Firstly, three frame models are established considering the effects of different heights by PKPM software. Then, the FEM, together with the plastic hinge model, is applied to simulate numerically the whole process of dynamic responses on the structures suffered with near-fault motions, and the effects of velocity pulse and non-pulse motions are compared. Finally, the damaging factors of the velocity pulse are demonstrated. The results show that the structural damage degree is related to the high-frequencies and the peak ground accelerations of velocity pulse motions. Moreover, when seismic responses of structures step into the plastic stage, the structural responses to the ground motion with velocity pulse are increased by considerable magnitudes compared to the motions without velocity pulses.