The surface of n-GaN is fabricated by photo-enhanced wet etching with the etchant of 0.1 M K2S2O8＋KOH and the illumination of Xe ultraviolet light. The n-GaN with an electrode on its surface is etched. Under the same etching condition, n-GaN with an electrode on its surface shows a higher etching rate but a lower root-mean-error(RMS) compared with n-GaN without an electrode. After etching, the surface of n-GaN is covered by hexagonal cones. Output power of the LED is improved by 88.5% after etching with 20 mA current.