Enhanced glow discharge plasma immersion ion implantation is self-consistently simulated using a three-dimensional PIC/MC model. The information about ion counts, space potential, plasma density and ion incident dose is obtained. The results show that the sheath has fully expanded at 5 μs. There is a stable equilibrium of ion counts at 15 μs, which corroborates the characteristic of self-sustaining glow discharge of EGD-PIII. In the space just below anode where is found a highest plasma density, verifying the electron focusing effect. The rate of implantation is steady and the incident dose is relatively uniform except at the rim of target. A higher pulse negative bias may increase the injection rate but reduce the dose uniformity at the same time.