GaN-based resonant-cavity light-emitting diodes (RCLEDs) have been fabricated on Si substrates with a current confinement by hydrogen (H) implantation. In order to ascertain the optimum implantation concentration for the current confinement layer of RCLEDs, the effects of implantation concentration (as-grown, 1013, 1014 and 1015 ions cm-2) on the characteristics of a p-GaN cladding layer were investigated in terms of Hall measurements, photoluminescence (PL) spectra and x-ray (XRD) diffraction. The properties of PL, XRD and contact resistance of the epi-LED wafers with different implantation concentrations were also analyzed. An optimum H-implantation concentration of 1014 ions cm-2 has been determined based on the current confinement performance. Under this condition, the 1014 ions cm-2 implanted RCLED sample shows the higher electroluminescence intensity than that of the SiO 2-insulated RCLED one. Furthermore, the light emission pattern of the 1014 ions cm-2 implanted RCLED also shows a superior directionality. The improved results could be attributed to the better current and photon confinements laterally in the light aperture.