Our preseut research was focused on the surface properies of the p-type gallium nitride (p-GaN) etched by inductively coupled plasma (ICP). Different methods were used to process the etched surface. The surface condition was investigated by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The current voltage measurement was used to show the I-V characteristics of Ni/Au contacts on the sample. The experimental result demonstrated that the NaOH treatment is effective in improving the material surface and the ohmic contact properties.