A novel approach to epitaxial GaN growth using the plasma-assisted ionized source beam epitaxy (PAISBE) was reported. To assist the growth of GaN, an accelerated partially ionized Ga source beam was employed along with an atomic nitrogen beam from an rf-discharge nitrogen plasma. The crystal property and surface morphology of the PAISBE-grown GaN films on sapphire (0001) were investigated using reflection high-energy electron diffraction, X-ray diffraction, and scanning electron microscopy. The optimum films were achieved with a partially ionized Ga beam at peak for a 0.4-μm-thick film. The buffer layer was a GaN film grown at 400°C. Observations showing the effects of different control parameters and, particularly, those exhibiting the advantages of PAISBE were reported.